Halacha
הלכה א
אֵין כָּשֵׁר לְעֵדוּת הַחֹדֶשׁ אֶלָּא שְׁנֵי אֲנָשִׁים כְּשֵׁרִים הָרְאוּיִין לְהָעִיד בְּכָל דָּבָר וְדָבָר. אֲבָל נָשִׁים וַעֲבָדִים הֲרֵי הֵן כִּשְׁאָר פְּסוּלֵי עֵדוּת וְאֵין מְעִידִין. אָב וּבְנוֹ שֶׁרָאוּ אֶת הַיָּרֵחַ יֵלְכוּ לְבֵית דִּין לְהָעִיד. לֹא מִפְּנֵי שֶׁעֵדוּת הַחֹדֶשׁ כְּשֵׁרָה בִּקְרוֹבִים אֶלָּא שֶׁאִם יִמָּצֵא אֶחָד מֵהֶן פָּסוּל מִפְּנֵי שֶׁהוּא גַּזְלָן וְכַיּוֹצֵא בּוֹ מִשְּׁאָר הַפַּסְלָנוּת יִצְטָרֵף הַשֵּׁנִי עִם אַחֵר וְיָעִידוּ. וְכָל הַפָּסוּל לְעֵדוּת מִדִּבְרֵי סוֹפְרִים אַף עַל פִּי שֶׁהוּא כָּשֵׁר מִן הַתּוֹרָה פָּסוּל לְעֵדוּת הַחֹדֶשׁ:
כסף משנה
1.
The only testimony that is acceptable with regard to [the sighting of] the new [moon] is that of two1For all evidence must be substantiated by the testimony of two witnesses, as implied by Deuteronomy 19:15 which states, "The testimony of a single witness will not stand." See Hilchot Edut, ch. 5. adult males2Both these concepts are implied by the Hebrew word anashim. who are fit to testify regarding all matters.3See Hilchot Edut, Chapters 9-10, 12-14. Women and slaves,4Who are not acceptable for testimony in court (Hilchot Edut 9:2,4). The slaves referred to here are "Canaanite slaves," gentiles purchased as slaves. A Jewish servant, eved ivri, may give testimony in court on this and other matters. by contrast, are like other unacceptable witnesses and may not testify.When a father and a son both see the new moon, they should both go the court to testify. Not because testimony regarding the [the sighting of] the new [moon] is acceptable [from witnesses who are] related, but because one of them may be disqualified because he is a thief or for other reasons, and the other will be able to join with another person and give testimony.
A person who is disqualified from serving as a witness by Rabbinical decree,5E.g., gamblers, usurers, and other individuals described in Hilchot Edut, Chapter 11. although he is acceptable according to the law of the Torah itself, may not serve as a witness with regard to [the sighting of] the new [moon].
הלכה ב
דִּין תּוֹרָה שֶׁאֵין מְדַקְדְּקִין בְּעֵדוּת הַחֹדֶשׁ. שֶׁאֲפִלּוּ קִדְּשׁוּ אֶת הַחֹדֶשׁ עַל פִּי עֵדִים וְנִמְצְאוּ זוֹמְמִין בְּעֵדוּת זוֹ הֲרֵי זֶה מְקֻדָּשׁ. לְפִיכָךְ הָיוּ בָּרִאשׁוֹנָה מְקַבְּלִין עֵדוּת הַחֹדֶשׁ מִכָּל אָדָם מִיִּשְׂרָאֵל שֶׁכָּל יִשְׂרָאֵל בְּחֶזְקַת כַּשְׁרוּת עַד שֶׁיִּוָּדַע לְךָ שֶׁזֶּה פָּסוּל. מִשֶּׁקִּלְקְלוּ הַבַּיְתוֹסִים וְהָיוּ שׂוֹכְרִין אֲנָשִׁים לְהָעִיד שֶׁרָאוּ וְהֵם לֹא רָאוּ הִתְקִינוּ שֶׁלֹּא יְקַבְּלוּ בֵּית דִּין עֵדוּת הַחֹדֶשׁ אֶלָּא מֵעֵדִים שֶׁמַּכִּירִין בֵּית דִּין אוֹתָן שֶׁהֵם כְּשֵׁרִים וְשֶׁיִּהְיוּ דּוֹרְשִׁין וְחוֹקְרִים בָּעֵדוּת:
כסף משנה
2.
According to the law of the Torah, there is no need to be precise regarding testimony about [the sighting of] the new [moon]. For even if the new moon was sanctified on the basis of the testimony of witnesses, and later it was discovered that those witnesses had perjured themselves,6More particularly, the term used by the Rambam, zomemim refers to witnesses who claimed that they saw the moon while they were located in a specific place at a specific time, and later it was proven that they had been in another place at that time. (See Hilchot Edut, Chapter 18.) [the new moon] remains sanctified.7See Halachah 10.Accordingly, in the early generations, testimony regarding [the sighting of] the new [moon] was accepted from any Jew [without further enquiry], for any Jew can be presumed to be an acceptable witness unless one knows with certainty that he is unacceptable. When the followers of Baithos8Avot D'Rabbi Natan 5:2 relates that Antigonus of Socho had two talented students, Tzadok and Baithos. When Antigonus taught: "Do not be like students serving a master in order to receive a reward," they turned away in disgust, commenting, "Is it proper for a worker to toil the entire day without receiving any recompense?"
They began splinter groups that rejected the core of Jewish practice and coveted material wealth. They found that they could not convince the majority of the people to reject the Torah entirely, so they adopted a different tactic. They claimed that they were true to Torah, but the only Torah that was Godly was the written law. The oral law, they maintained, was merely a human invention.
This thesis was only a ruse to sway the people from the performance of the mitzvot. Accordingly, the Sages would refer to all those who deny the Torah and its tradition as Sadducees (from Tzadok) or Baithosees (from Baithos) [the Rambam's Commentary on the Mishnah, Avot 1:3]. Not only did these individuals scorn Torah observance themselves, but they tried, as indicated by this halachah, to undermine the observance of the Jewish nation as a whole.
Our translation follows the standard printed text of the Mishneh Torah. Many original printings and manuscripts state minnim, "non-believers," rather than "the followers of Baithos." Similarly, the Rambam's source, Rosh HaShanah 2:1, uses this term. Some consider this as a reference to the early Christians. began conducting themselves in a debased manner and would hire people9Rosh HaShanah 22b relates that the Sadducees paid witnesses 400 zuzim to testify falsely with regard to the sighting of the moon. to testify that they had seen the moon when in fact they had not, the court decreed that it would accept testimony regarding [the sighting of] the new [moon] only from witnesses whom the court knew to be acceptable. Moreover, they would examine and question their testimony.
הלכה ג
לְפִיכָךְ אִם לֹא יִהְיוּ בֵּית דִּין יוֹדְעִים אֶת הָעֵדִים שֶׁרָאוּ אֶת הַיָּרֵחַ מְשַׁלְּחִין אַנְשֵׁי הָעִיר שֶׁנִּרְאָה בָּהּ עִם הָעֵדִים שֶׁרָאוּ עֵדִים אֲחֵרִים שֶׁמְּזַכִּין אוֹתָן לְבֵית דִּין וּמוֹדִיעִין אוֹתָן שֶׁאֵלּוּ כְּשֵׁרִים הֵם וְאַחַר כָּךְ מְקַבְּלִין מֵהֶם:
כסף משנה
3.
Therefore, if the [High] Court did not know [the character of] the witnesses who sighted the moon, the inhabitants of the city where the moon was sighted would send other witnesses10The Rambam uses a plural term, implying that two character witnesses are required. This prerequisite is apparent from Rosh HaShanah 22b. The Jerusalem Talmud (Rosh HaShanah 2:1), by contrast, requires only one character witness. together with the witnesses who saw the moon to substantiate their character to the court, and inform [the judges] that they are acceptable [witnesses]. [Only] afterwards would the court accept their [testimony].הלכה ד
בֵּית דִּין מְחַשְּׁבִין בַּדְּרָכִים שֶׁהָאִיצְטַגְנִינִין מְחַשְּׁבִין בָּהֶם וְיוֹדְעִין הַלְּבָנָה כְּשֶׁתֵּרָאֶה בְּחֹדֶשׁ זֶה אִם תִּהְיֶה בִּצְפוֹן הַשֶּׁמֶשׁ אוֹ בִּדְרוֹמָהּ וְאִם תִּהְיֶה רְחָבָה אוֹ קְצָרָה וּלְהֵיכָן יִהְיוּ רָאשֵׁי קַרְנֶיהָ נוֹטִין. וּכְשֶׁיָּבוֹאוּ הָעֵדִים לְהָעִיד בּוֹדְקִין אוֹתָם כֵּיצַד רְאִיתֶם אוֹתָהּ בְּצָפוֹן אוֹ בְּדָרוֹם. לְהֵיכָן הָיוּ קַרְנֶיהָ נוֹטוֹת. כַּמָּה הָיְתָה גְּבוֹהָה בִּרְאִיַּת עֵינֵיכֶם וְכַמָּה הָיְתָה רְחָבָה. אִם נִמְצְאוּ דִּבְרֵיהֶם מְכֻוָּנִין לְמַה שֶּׁנּוֹדַע בַּחֶשְׁבּוֹן מְקַבְּלִין אוֹתָם וְאִם לֹא נִמְצְאוּ דִּבְרֵיהֶם מְכֻוָּנִין אֵין מְקַבְּלִין אוֹתָם:
כסף משנה
4.
The court would make calculations in a manner resembling the calculations of the astronomers, and would know whether the position of the moon - when it would be sighted - would be to the north of the sun, or to its south,11As the Rambam states in his Commentary on the Mishnah, Rosh HaShanah 2:7, this refers to the latitude of the moon. This subject is explained in Chapter 16. if its [crescent] would be wide or narrow,12As the Rambam explains in his Commentary on the Mishnah (loc. cit.), the size of the moon's crescent grows as it moves further away from the sun. and the direction in which its corners would be pointed.13See Chapter 19 for an explanation of how the court can determine these matters.When the witnesses came to testify, they would ask them: "Where did you see [the moon]: to the north or to the south [of the sun]?", "In which direction were its corners pointed?", "How high and how wide did it appear to you?" If their replies were suitable, their testimony was accepted. If their replies were not suitable, their testimony was not accepted.
הלכה ה
אָמְרוּ הָעֵדִים רְאִינוּהוּ בַּמַּיִם אוֹ בֶּעָבִים אוֹ בַּעֲשָׁשִׁית. אוֹ שֶׁרָאוּ מִקְצָתוֹ בָּרָקִיעַ וּמִקְצָתוֹ בֶּעָבִים אוֹ בַּמַּיִם אוֹ בַּעֲשָׁשִׁית אֵין זוֹ רְאִיָּה וְאֵין מְקַדְּשִׁין עַל רְאִיָּה זֹאת. אָמַר אֶחָד רְאִיתִיו גָּבוֹהַּ בְּעֵינַי כְּמוֹ שְׁתֵּי קוֹמוֹת וְאָמַר הַשֵּׁנִי כְּמוֹ שָׁלֹשׁ קוֹמוֹת הָיָה גָּבוֹהַּ מִצְטָרְפִין. אָמַר הָאֶחָד כְּמוֹ שָׁלֹשׁ קוֹמוֹת וְהַשֵּׁנִי אוֹמֵר כְּמוֹ חָמֵשׁ אֵין מִצְטָרְפִין. וּמִצְטָרֵף אֶחָד מֵהֶם עִם שֵׁנִי שֶׁיָּעִיד כְּמוֹתוֹ אוֹ יִהְיֶה בֵּינֵיהֶן קוֹמָה אַחַת:
כסף משנה
5.
If the witnesses say, "We saw [the reflection of the moon] in water," or "...[its form] behind the clouds," or "...[its reflection] in a mirror," [what they] saw is of no [consequence], and this sighting cannot be used as the basis for sanctifying [the new moon].14To sanctify the moon, it is necessary to see the moon itself - and not its reflection - and to see it clearly, not as it is hidden by clouds. [The same law applies if the witnesses say,] "We saw a portion [of the moon] in the heavens, and a portion of [its form] behind the clouds," "...a portion [reflected] in water," or "...a portion [reflected] in a mirror."If one [potential witness says,] "I saw it and it appeared to me approximately two storeys high," and another [potential witness] says, "It was three storeys high," their testimonies may be combined15Although there is a discrepancy between them, the two testimonies are not considered to contradict each other, since it is possible for a person to err slightly in making such an estimation. [and the moon sanctified on this basis]. If, however, one says "It was approximately three storeys high," and the other says, "It was approximately five storeys high," their testimonies may not be joined together.16For this discrepancy is too great for the two to be considered a single statement. Either one of them, however, may join together with another witness who gives identical testimony, or [who gives testimony] involving a discrepancy of merely one storey.
הלכה ו
אָמְרוּ רְאִינוּהוּ בְּלֹא כַּוָּנָה וְכֵיוָן שֶׁהִתְבּוֹנַנְנוּ בּוֹ וְנִתְכַּוַּנְנוּ לִרְאוֹתוֹ לְהָעִיד שׁוּב לֹא רְאִינוּהוּ אֵין זוֹ עֵדוּת וְאֵין מְקַדְּשִׁין עָלֶיהָ. שֶׁמָּא עָבִים נִתְקַשְּׁרוּ וְנִרְאוּ כַּלְּבָנָה וְכָלוּ וְהָלְכוּ לָהֶם. אָמְרוּ עֵדִים רְאִינוּהוּ בְּיוֹם תִּשְׁעָה וְעֶשְׂרִים שַׁחֲרִית בַּמִּזְרָח קֹדֶם שֶׁתַּעֲלֶה הַשֶּׁמֶשׁ וּרְאִינוּהוּ עַרְבִית בַּמַּעֲרָב בְּלֵיל שְׁלֹשִׁים הֲרֵי אֵלּוּ נֶאֱמָנִים וּמְקַדְּשִׁין עַל רְאִיָּה זוֹ שֶׁהֲרֵי רָאוּהוּ בִּזְמַנּוֹ. אֲבָל הָרְאִיָּה שֶׁאָמְרוּ שֶׁרָאוּהוּ בְּשַׁחֲרִית אֵין נִזְקָקִין לָהּ שֶׁאֵין אָנוּ אַחְרָאִין לִרְאִיַּת שַׁחֲרִית וּבְיָדוּעַ שֶׁהֶעָבִים הֵם שֶׁנִּתְקַשְּׁרוּ וְנִרְאָה לָהֶם כִּלְבָנָה. וְכֵן אִם רָאוּהוּ בִּזְמַנּוֹ וּבְלֵיל עִבּוּרוֹ לֹא נִרְאָה הֲרֵי אֵלּוּ נֶאֱמָנִין שֶׁאֵין אָנוּ אַחְרָאִין אֶלָּא לִרְאִיַּת לֵיל שְׁלֹשִׁים בִּלְבַד:
כסף משנה
6.
If witnesses say, "We saw [the moon] without concentrating our attention, and, afterwards, when we concentrated our attention with the intent of sighting it so that we could testify, we did not see it," this is not considered [valid] testimony, and it cannot serve as the basis for sanctifying [the new moon]. Perhaps clouds came together, and appeared like the moon, and afterwards became dispersed.17Rosh HaShanah 24a and 25a mentions instances where the conjunction of the clouds appeared to resemble the moon.If witnesses say, "We saw [the moon] on the twenty-ninth [day] in the morning in the east before sunrise, and [afterwards,] in the evening, we saw it in the west on the thirtieth night," their testimony is believed, and the moon can be sanctified on this basis. [The rationale is] that they saw [the moon] at its appropriate time. [Their testimony] about [what they thought] they saw in the morning is disregarded. We need not pay any attention to what they saw in the morning, for it is obvious that it was the conjunction of clouds that appeared to them as the moon.18The Rambam's statements are based on his interpretation of the difference of opinion between Rabban Gamliel and Rabbi Yochanan ben Nuri mentioned in Rosh HaShanah 2:9. (See the Rambam's Commentary on the Mishnah for a detailed analysis of this matter.)
Rabbi Yochanan ben Nuri maintains that the witnesses' testimony should be disregarded, because it cannot possibly be true. Everyone knows that, at the beginning of the month, the moon always appears on the western horizon for a brief period after the setting of the sun. At this time of the month, seeing it in the morning, before sunrise, is impossible. (See Chapters 15 and 17 for an explanation of this phenomenon.) Since the testimony of these witnesses contains an obvious error, the testimony should be disregarded entirely.
Rabban Gamliel, as his opinion is explained by the Rambam, was aware of this astronomical concept as well. Nevertheless, in the instance mentioned in the Mishnah, he knew that according to the calculations, it would have been possible for the moon to have been sighted on the night mentioned by the witnesses. Why then, he argued, should their testimony be discounted entirely because of the error they made regarding the morning. The fact that then, they mistook the condensation of clouds for the moon should not cause their testimony to be disregarded entirely.
Similarly, if [witnesses claim] to have seen the moon at its appropriate time, but it was not seen on the thirty-first night, their [testimony] is believed. For what is significant for us is only the sighting [of the moon] on the thirtieth night.19This represents a parallel difference of opinion mentioned in Rosh HaShanah (op. cit.). Rabbi Dosa ben Hyrkanos maintains that it is impossible for the moon to be sighted on one night, and then for it not to be sighted on the following night.
Rabban Gamliel (as his position is explained by the Rambam in his Commentary on the Mishnah) accepted the witnesses' testimony in this instance, because he knew that, according to the calculations, it was possible for the moon to be sighted on the thirtieth night. The fact that it was not sighted again on the thirty-first night was merely a matter of circumstance: no one was trying to see it, their view was obstructed by clouds, or the like.
הלכה ז
כֵּיצַד מְקַבְּלִין עֵדוּת הַחֹדֶשׁ. כָּל מִי שֶׁרָאוּי לְהָעִיד שֶׁרָאָה אֶת הַיָּרֵחַ בָּא לְבֵית דִּין. וּבֵית דִּין מַכְנִיסִים אוֹתָן כֻּלָּן לְמָקוֹם אֶחָד וְעוֹשִׂין לָהֶן סְעֻדּוֹת גְּדוֹלוֹת כְּדֵי שֶׁיִּהְיוּ הָעָם רְגִילִין לָבוֹא. וְזוּג שֶׁבָּא רִאשׁוֹן בּוֹדְקִין אוֹתָן רִאשׁוֹן בַּבְּדִיקוֹת שֶׁאָמַרְנוּ. מַכְנִיסִין אֶת הַגָּדוֹל וְשׁוֹאֲלִין אוֹתוֹ. נִמְצְאוּ דְּבָרָיו מְכֻוָּנִים לַחֶשְׁבּוֹן מַכְנִיסִים אֶת חֲבֵרוֹ. נִמְצְאוּ דִּבְרֵיהֶם מְכֻוָּנִין עֵדוּתָן קַיֶּמֶת. וּשְׁאָר כָּל הַזּוּגוֹת שׁוֹאֲלִין אוֹתָם רָאשֵׁי דְּבָרִים. לֹא שֶׁצְּרִיכִים לָהֶם אֶלָּא כְּדֵי שֶׁלֹּא יֵצְאוּ בְּפַחֵי נֶפֶשׁ, כְּדֵי שֶׁיִּהְיוּ רְגִילִין לָבוֹא:
כסף משנה
7.
What is the process through which the testimony regarding the sighting of the moon is accepted? Anyone who saw the moon and is fit to testify20I.e., there is no benefit to be derived from a witness whose testimony will not be accepted by the court because of his conduct - e.g., a transgressor, a gambler, or a usurer. should come to the court. The [judges] should bring them all to a single place,21Rosh HaShanah 23b states that there was a large courtyard in Jerusalem called "the house of Ya'azak" where the witnesses would gather. and should make a large feast for them, so that people will come regularly. The pair [of witnesses] who arrive first are examined first according to the questions mentioned previously.22In Halachah 4. The one of greater stature is invited [into a private chamber] first and asked these questions. If his testimony is accurate according to [the data that the court arrives at through] calculations, they invite his colleague in. If their statements are comparable,23See Halachah 5. their testimony is substantiated.[Afterwards,] the remaining pairs are asked questions of a broader nature. [In truth,] their testimony is not required at all, [and they are being asked] only so they will not depart disheartened, so that they will come frequently [in the future].24The Rambam (based on Rosh HaShanah 2:7) is communicating an important lesson in human dynamics. Since the court might need these witnesses in the future, it is important that they feel that consideration is shown to them, and that their coming was not futile.
הלכה ח
וְאַחַר כָּךְ אַחַר שֶׁתִּתְקַיֵּם הָעֵדוּת רֹאשׁ בֵּית דִּין אוֹמֵר מְקֻדָּשׁ וְכָל הָעָם עוֹנִים אַחֲרָיו מְקֻדָּשׁ מְקֻדָּשׁ. וְאֵין מְקַדְּשִׁין אֶת הַחֹדֶשׁ אֶלָּא בִּשְׁלֹשָׁה. וְאֵין מְחַשְּׁבִין אֶלָּא בִּשְׁלֹשָׁה. וְאֵין מְקַדְּשִׁין אֶלָּא חֹדֶשׁ שֶׁנִּרְאֶה בִּזְמַנּוֹ. וְאֵין מְקַדְּשִׁין אֶלָּא בַּיּוֹם וְאִם קִדְּשׁוּהוּ בַּלַּיְלָה אֵינוֹ מְקֻדָּשׁ. ואֲפִלּוּ רָאוּהוּ בֵּית דִּין וְכָל יִשְׂרָאֵל וְלֹא אָמְרוּ בֵּית דִּין מְקֻדָּשׁ עַד שֶׁחָשְׁכָה לֵיל אֶחָד וּשְׁלֹשִׁים. אוֹ שֶׁנֶּחְקְרוּ הָעֵדִים וְלֹא הִסְפִּיקוּ בֵּית דִּין לוֹמַר מְקֻדָּשׁ עַד שֶׁחָשְׁכָה לֵיל אֶחָד וּשְׁלֹשִׁים. אֵין מְקַדְּשִׁין אוֹתוֹ וְיִהְיֶה הַחֹדֶשׁ מְעֻבָּר וְלֹא יִהְיֶה רֹאשׁ חֹדֶשׁ אֶלָּא יוֹם אֶחָד וּשְׁלֹשִׁים אַף עַל פִּי שֶׁנִּרְאֵית בְּלֵיל שְׁלֹשִׁים. שֶׁאֵין הָרְאִיָּה קוֹבַעַת אֶלָּא בֵּית דִּין שֶׁאָמְרוּ מְקֻדָּשׁ הֵם שֶׁקּוֹבְעִין:
כסף משנה
8.
Afterwards - i.e., after [the witnesses'] testimony is substantiated - the head of the court declares, "It has been sanctified." And all the people respond, "It has been sanctified. It has been sanctified."A minimum of three judges is required to sanctify the new moon.25Rosh HaShanah 25b derives this concept as follows: The commandment "This month shall be for you..." was addressed to both Moses and Aaron, implying that at least two judges are necessary. A court must be composed of an odd number of judges, and hence a third judge is required. Similarly, the calculations [regarding the moon's position] must be made by three judges. The new moon is sanctified only when it is sighted at its appropriate time.26I.e., as the Rambam continues to explain, for the new month to be sanctified, the moon must be sighted on the thirtieth night, the witnesses must testify on the thirtieth day, and the court must declare the month to be sanctified - all before sunset of that day. Moreover, the moon is sanctified only during the day.27Based on Psalms 81:4-5, Rosh HaShanah 25b draws an equation between the sighting of the new moon and the delivery of a judgment. Just as a judgment may be delivered only during the day, so too, the mitzvah of the sanctifying the new moon applies only by day. If it was sanctified at night, the sanctification is of no consequence.
Furthermore, even if the court and the entire Jewish people saw the moon, but the court did not declare that "It has been sanctified"28In his Commentary on the Mishnah, Rosh HaShanah 3:1, the Rambam explains that one might think that since the court and the entire Jewish people saw the moon, there was no need to sanctify the new month. Therefore, as he concludes in this halachah, it is necessary to emphasize that it is the sanctification of the court that establishes the new month, and not the sighting of the moon alone. before the nightfall beginning the thirty-first day, or if the witnesses were cross-examined, but afterwards the court was not able to declare that "It has been sanctified" before the nightfall beginning the thirty-first day,29Rosh HaShanah (loc. cit.) explains that although a decision regarding a monetary case may be rendered at night if the testimony was received by the court during the day, this concept does not apply regarding the sanctification of the new month. The court must actually sanctify the new month during the day. it should not be sanctified,30Based on Chapter 3, Halachot 15-18, it would appear that the Rambam's intent is that, since the new month was not sanctified at its appropriate time, the court endeavors to have the witnesses' testimony disqualified. If, however, the witnesses' testimony is substantiated despite the court's efforts, the month can be sanctified retroactively. and the month should be full. Despite the fact that the moon was sighted on the thirtieth night, it is the thirty- first day that will be Rosh Chodesh. For [the sanctification of the new month] is not established by the sighting of the moon, but by the court that declares, "It has been sanctified."31As mentioned in Chapter 1, Halachah 5, the mitzvah of sanctifying the new month has been entrusted to the court.
הלכה ט
רָאוּהוּ בֵּית דִּין עַצְמָן בְּסוֹף יוֹם תִּשְׁעָה וְעֶשְׂרִים. אִם עֲדַיִן לֹא יָצָא כּוֹכַב לֵיל שְׁלֹשִׁים. בֵּית דִּין אוֹמְרִים מְקֻדָּשׁ שֶׁעֲדַיִן יוֹם הוּא. וְאִם רָאוּהוּ בְּלֵיל שְׁלֹשִׁים אַחַר שֶׁיָּצְאוּ שְׁנֵי כּוֹכָבִים. לְמָחָר מוֹשִׁיבִין שְׁנֵי דַּיָּנִין אֵצֶל אֶחָד מֵהֶם וְיָעִידוּ הַשְּׁנַיִם בִּפְנֵי הַשְּׁלֹשָׁה וִיקַדְּשׁוּהוּ הַשְּׁלֹשָׁה:
כסף משנה
9.
If the court themselves see [the new moon] at the conclusion of the twenty-ninth day, before a star has emerged on the thirtieth night, the court may declare, "It has been sanctified; it has been sanctified,"32Rosh HaShanah 25b explains that this teaches us that hearing the testimony of the witnesses is not more effective than the actual sighting of the moon itself. for it is still day.33In his Commentary on the Mishnah (Rosh HaShanah 3:1), the Rambam writes that although the sun has set, the night does not begin until the appearance of the stars, and it is still possible to sanctify the new moon.(The Rambam's wording in this halachah and in the related portions of his Commentary on the Mishnah have raised questions concerning his conception of the limits of the day, the night, and the intermediate period referred to as beyn hash'mashot. See the Radbaz (Vol. V, Responsum 1379), the Ralbach, the Or Sameach and others, who address themselves to this issue.)
It is also significant to mention that Rashi (Rosh HaShanah, loc. cit.) and others differ with the Rambam's interpretation of the Mishnah, and consider it as referring to the sighting of the moon at the conclusion of the thirtieth day, on the eve of the thirty- first.
If [the judges] sight the moon on the night of the thirtieth day after two stars have appeared,34From this time onward, they can no longer sanctify the new month on the basis of their sighting alone. Instead, the procedure outlined by the Rambam must be followed. [they should adhere to the following procedure]. On the morrow, two other judges join one of the three [to form a court]. The other two [judges] then testify before [this court] of three, who then [sanctify the new month].
הלכה י
בֵּית דִּין שֶׁקִּדְּשׁוּ אֶת הַחֹדֶשׁ בֵּין שׁוֹגְגִין בֵּין מֻטְעִין בֵּין אֲנוּסִים הֲרֵי זֶה מְקֻדָּשׁ וְחַיָּבִין הַכּל לְתַקֵּן הַמּוֹעֲדוֹת עַל הַיּוֹם שֶׁקִּדְּשׁוּ בּוֹ. אַף עַל פִּי שֶׁזֶּה יוֹדֵעַ שֶׁטָּעוּ חַיָּב לִסְמֹךְ עֲלֵיהֶם שֶׁאֵין הַדָּבָר מָסוּר אֶלָּא לָהֶם וּמִי שֶׁצִּוָּה לִשְׁמֹר הַמּוֹעֲדוֹת הוּא צִוָּה לִסְמֹךְ עֲלֵיהֶם שֶׁנֶּאֱמַר אֲשֶׁר תִּקְרְאוּ אֹתָם וְגוֹ':
כסף משנה
10.
Once the court sanctifies the new month, it remains sanctified regardless of whether they erred unwittingly, they were led astray [by false witnesses], or they were forced [to sanctify it].35Significantly, instead of mentioning the court as being forced to sanctify the month on the wrong day, Rosh HaShanah 25a states "even if they purposefully sanctified the moon on the wrong day" - i.e., they accepted the testimony of witnesses even when they knew that it was flimsy. The Rambam chooses not to mention such an instance, and instead quotes the Mechilta D'Rashbi and the Sifra. We are required to calculate [the dates of] the festivals based on the day that they sanctified [as the beginning of the new month].Even if [a person] knows that [the court] erred, he is obligated to rely on them,36Rosh HaShanah 2:10 relates that once Rabbi Yehoshua differed with Rabban Gamliel concerning the acceptance of the testimony of witnesses with regard to Rosh HaShanah. Since Rabban Gamliel was the head of the High Court, his opinion was accepted. To emphasize the importance of following the necessity for uniform adherence to the decisions of the court, Rabban Gamliel ordered Rabbi Yehoshua to appear before him carrying his staff and his wallet on the day that Rabbi Yehoshua thought should be considered as Yom Kippur.
After consulting with his colleagues, Rabbi Yehoshua obeyed Rabban Gamliel's instructions. Afterwards, Rabban Gamliel honored Rabbi Yehoshua for his humility and deference to the court's authority. for the matter is entrusted to them alone. The One who commanded us to observe the festivals is the One who commanded [us] to rely on them, as [implied by Leviticus 23:2]: "Which you will pronounce as days of holy convocation."37אתם, meaning "which" in the above verse, can also mean "you," when vocalized differently. Thus, the authority of "you," the Jewish court to whom this matter is entrusted, is emphasized more powerfully (Rosh HaShanah, loc. cit.).