Halacha

הלכה א
כָּל הַמִּטַּלְטְלִין קוֹנִין זֶה אֶת זֶה. כֵּיצַד. הֶחְלִיף פָּרָה בַּחֲמוֹר אוֹ יַיִן בְּשֶׁמֶן אַף עַל פִּי שֶׁמַּקְפִּידִין עַל הַדָּמִים וְשִׁעֲרוּ כַּמָּה שָׁוֶה זֶה וְכַמָּה שָׁוֶה זֶה וְאַחַר כָּךְ הֶחְלִיפוּ. כֵּיוָן שֶׁמָּשַׁךְ הָאֶחָד אוֹ הִגְבִּיהוֹ קָנָה הַשֵּׁנִי הַמִּטַּלְטְלִין הָאֲחֵרִים בְּכָל מָקוֹם שֶׁהֵם וְנַעֲשׂוּ בִּרְשׁוּתוֹ. וְאַף עַל פִּי שֶׁעֲדַיִן לֹא מְשָׁכָן:
כסף משנה
1.
The exchange of any movable property brings about a binding transaction. What is implied? If a person exchanges a cow for a donkey, or wine for oil, once one performs meshichah or lifts up the article that he intends to acquire, the other person acquires the second form of movable property stipulated in the exchange, wherever it is located. It is considered to have entered his domain, even though he has not performed meshichah upon it.
The above applies although both parties to the transaction are particular about the price, have determined how much this article is worth and how much the other article is worth, and exchanged them after making that determination.

הלכה ב
הֶחְלִיף חֲמוֹר בְּפָרָה וְטָלֶה וּמָשַׁךְ הַפָּרָה וַעֲדַיִן לֹא מָשַׁךְ אֶת הַטָּלֶה לֹא קָנָה שֶׁאֵין כָּאן מְשִׁיכָה גְּמוּרָה. וְכֵן כָּל כַּיּוֹצֵא בָּהֶן:
כסף משנה
2.
When a person exchanges a donkey for a cow and a lamb, if he performs meshichah on the cow but not on the lamb, the acquisition is not concluded, for he did not complete the meshichah. The same principle applies in all analogous situations.

הלכה ג
דָּמִים שֶׁאֵין מַקְפִּידִין עֲלֵיהֶם הֲרֵי הֵן כִּשְׁאָר מִטַּלְטְלִין וְקוֹנִין. כֵּיצַד. הֲרֵי שֶׁחָפַן מָעוֹת בְּלֹא מִשְׁקָל וּבְלֹא מִנְיָן אֶלָּא נְטָלָן אַכְסָרָה. וְאָמַר לוֹ מְכֹר לִי פָּרָתְךָ אוֹ יַיִן זֶה בְּאֵלּוּ וְנָתַן לוֹ אֶת הַדָּמִים קָנָה וְאֵין אֶחָד מֵהֶם יָכוֹל לַחְזֹר בּוֹ. שֶׁזֶּה דָּבָר שֶׁאֵינוֹ מָצוּי הוּא וְלֹא הִצְרִיכוּ בּוֹ מְשִׁיכָה:
כסף משנה
3.
When one is not precise about the amount of money involved in a transaction, the money is considered in the same way as other types of movable property, and its exchange brings about a binding transaction.
What is implied? A person scooped up coins without weighing them or counting them, but rather took an estimated amount, said: "Sell me your cow...," or "...this wine, for these coins," and gave him the coins, the transaction is completed; neither party may retract. Since this is an uncommon situation, our Sages did not require the purchaser to perform meshichah.

הלכה ד
וְכֵן רְאוּבֵן שֶׁמָּכַר מִטַּלְטְלִין לְשִׁמְעוֹן בַּחֲמִשִּׁים זוּז. וְקָנָה שִׁמְעוֹן הַמִּטַּלְטְלִין וְנִתְחַיֵּב בְּדָמִים. וְאַחַר שֶׁנִּתְחַיֵּב שִׁמְעוֹן בַּחֲמִשִּׁים זוּז אֵלּוּ הָיָה לוֹ יַיִן אוֹ בְּהֵמָה אוֹ עֶבֶד וְכַיּוֹצֵא בָּהֶן מִשְּׁאָר הַמִּטַּלְטְלִין וְהָיָה רוֹצֶה לְמָכְרָן. וְאָמַר לוֹ רְאוּבֵן מְכֹר אוֹתוֹ לִי בַּחֲמִשִּׁים זוּז שֶׁיֵּשׁ לִי בְּיָדְךָ דְּמֵי הַמֶּכֶר וְאָמַר לוֹ הֵן. קָנָה רְאוּבֵן הַמִּטַּלְטְלִין בְּכָל מָקוֹם שֶׁהֵן וְאַף עַל פִּי שֶׁלֹּא מָשַׁךְ וְלֹא הִגְבִּיהַּ. שֶׁגַּם זֶה דָּבָר שֶׁאֵינוֹ מָצוּי הוּא וְלֹא הִצְרִיכוּ בּוֹ מְשִׁיכָה. אֲבָל אִם הָיָה חוֹב לוֹ עָלָיו שֶׁלֹּא מֵחֲמַת הַמֶּכֶר וְאָמַר לוֹ מְכֹר לִי מִטַּלְטְלִין בַּחוֹב שֶׁיֵּשׁ לִי אֶצְלְךָ וְרָצוּ שְׁנֵיהֶם. לֹא קָנָה עַד שֶׁיַּגְבִּיהַּ. אוֹ יִמְשֹׁךְ דָּבָר שֶׁאֵין דַּרְכּוֹ לְהַגְבִּיהַּ. אוֹ יִקְנֶה בְּאֶחָד מֵהַדְּרָכִים שֶׁהַמִּטַּלְטְלִין נִקְנִין בָּהּ:
כסף משנה
4.
Similarly, movable property can be acquired without meshichah in the following situation. Reuven sold movable property to Shimon for 50 zuz. Shimon acquired the movable property and obligated himself to pay Reuven the price agreed upon. After Shimon became obligated to Reuven for these 50 zuz, he desired to sell wine, an animal, a servant or other similar movable property. Reuven told him: "Sell that object to me for the 50 zuz that you owe me for the sale," and Shimon agreed.
Reuven acquires the movable property regardless of where it is located, even though he neither performed meshichah nor lifted the object up. The rationale is that this also is an abnormal circumstance, and our Sages did not require meshichah.
When, by contrast, a person is in debt for reasons other than a sale, and his creditor tells him: "Sell me the movable property for the debt that you owe me," even though both agree, the transaction is not completed until he lifts up the object, performs meshichah on an object that is not usually lifted up, or acquires it through other means by which movable property can be acquired.

הלכה ה
הַקַּרְקָעוֹת וְהָעֲבָדִים וְהַבְּהֵמָה וּשְׁאָר כָּל הַמִּטַּלְטְלִין כָּל אֶחָד מֵהֶן נִקְנֶה בַּחֲלִיפִין וְהוּא הַנִּקְרָא קִנְיָן. וְעִקַּר הַדֶּרֶךְ הַזֹּאת שֶׁיִּתֵּן הַקּוֹנֶה לַמַּקְנֶה כְּלִי כָּל שֶׁהוּא וְיֹאמַר לוֹ קְנֵה כְּלִי זֶה חֵלֶף הֶחָצֵר. אוֹ הַיַּיִן. אוֹ הַבְּהֵמָה. אוֹ הָעֶבֶד שֶׁמָּכַרְתָּ לִי בְּכָךְ וְכָךְ. כֵּיוָן שֶׁהִגְבִּיהַּ הַמּוֹכֵר אֶת הַכְּלִי וְקָנָהוּ קָנָה הַלּוֹקֵחַ אוֹתוֹ הַקַּרְקַע אוֹ אוֹתָן הַמִּטַּלְטְלִין אַף עַל פִּי שֶׁעֲדַיִן לֹא מְשָׁכָן וְלֹא נָתַן הַדָּמִים. וְאֵין אֶחָד מֵהֶן יָכוֹל לַחְזֹר בּוֹ:
כסף משנה
5.
Landed property, servants, livestock and all other movable property can be acquired through the kinyan referred to as chalifin. This way of finalizing a transaction is so commonly used that it is also referred to as kinyan.
The fundamental manner in which such a transaction is effected is as follows: The purchaser gives the seller any type of article and tells him: "Acquire this article in exchange for the courtyard,..." "...wine,..." "...animal,..."or "...servant that you sold me in exchange for this and this amount of money."
Once this statement is made, when the seller lifts up the article and acquires it, the purchaser acquires that landed property or that movable property even though he did not perform meshichah or pay the money. Neither of the parties involved can retract.

הלכה ו
אֵין קוֹנִין אֶלָּא בְּכֵלִים וְאַף עַל פִּי שֶׁאֵין בּוֹ שְׁוֵה פְּרוּטָה. וְאֵין קוֹנִין בְּדָבָר שֶׁאָסוּר בַּהֲנָאָה. וְלֹא בְּפֵרוֹת וְלֹא בְּמַטְבֵּעַ. וְאֵין קוֹנִין בְּכֵלָיו שֶׁל מוֹכֵר אֶלָּא בְּכֵלָיו שֶׁל לוֹקֵחַ:
כסף משנה
6.
Such a transaction may be completed only through the use of a utensil. A utensil is effective, however, even if it is not worth a p'rutah.
Such a transaction may not be completed using an article from which it is forbidden to benefit, nor with produce, nor with a coin.
Such a transaction may not be completed using an article belonging to the seller; only one belonging to the purchaser.

הלכה ז
הִקְנָה אֶחָד כְּלִי לַמּוֹכֵר כְּדֵי שֶׁיִּקְנֶה הַלּוֹקֵחַ אוֹתוֹ הַמִּמְכָּר זָכָה הַלּוֹקֵחַ. וְאַף עַל פִּי שֶׁהִקְנָה לוֹ הַכְּלִי עַל מְנָת לְהַחְזִירוֹ נִקְנָה הַמִּקָּח וְזָכָה בּוֹ הַלּוֹקֵחַ. שֶׁהַמַּתָּנָה עַל מְנָת לְהַחְזִיר שְׁמָהּ מַתָּנָה. אַף עַל פִּי שֶׁלֹּא תָּפַס הַמּוֹכֵר כָּל הַכְּלִי שֶׁהִקְנָהוּ חֵלֶף מִמְכָּרוֹ אֶלָּא אָחַז מִקְצָתוֹ וְאָחַז הַמַּקְנֶה לוֹ מִקְצָתוֹ קָנָה הַלּוֹקֵחַ. וְהוּא שֶׁאָחַז מִמֶּנּוּ כְּדֵי שִׁעוּר כְּלִי אוֹ יֹאחֲזֶנּוּ אֲחִיזָה שֶׁהוּא יָכוֹל לְנַתֵּק אֶת כָּל הַכְּלִי מִיַּד הַמַּקְנֶה לוֹ. לְפִיכָךְ אִם הִקְנָה לוֹ בְּמִקְצָת הַבֶּגֶד צָרִיךְ שֶׁיֶּאֱחֹז מִן הַבֶּגֶד שָׁלֹשׁ אֶצְבָּעוֹת. שֶׁאִם יִפְסֹק מִמָּקוֹם שֶׁאָחַז הֲרֵי הוּא כְּלִי בִּפְנֵי עַצְמוֹ. שֶׁשָּׁלֹשׁ אֶצְבָּעוֹת מִבֶּגֶד קָרוּי כְּלִי כְּמוֹ שֶׁבֵּאַרְנוּ בְּעִנְיַן טֻמְאַת בְּגָדִים. וְכֵן אִם אָחַז פָּחוֹת מִשָּׁלֹשׁ וְהָיָה יָכוֹל לְנַתֵּק כָּל הַכְּלִי קָנָה:
כסף משנה
7.
When a third party transfers a utensil to the seller so that the purchaser will acquire merchandise that was designated, the purchaser acquires it.
Even though he transfers the utensil to him with the intent that it be returned, the transaction is binding, and the purchaser acquires the merchandise intended. For a gift that is given with the stipulation that it be returned is nevertheless considered a gift.
Moreover, even if the seller does not take hold of the entire utensil that was transferred to him in exchange for his merchandise, but rather holds a portion of it, and the person transferring the utensil to him holds the other portion, the purchaser acquires the merchandise, provided [the seller] holds a portion of the utensil that can itself be considered to be a utensil, or grabs it in a manner in which he would be able to pull the entire utensil from the hands of the person transferring it into his own possession.
Therefore, if the person transferred a portion of a garment to a seller, the seller must hold a portion of the garment the size of three fingerbreadths. Thus, if he cuts off the portion that he is holding, it would be considered a utensil in its own right. For a portion of a garment the size of three fingerbreadths is considered a garment, as has been explained with regard to the subject of the ritual impurity of garments. Similarly, if the seller holds on to a portion smaller than three fingerbreadths but could pull the entire garment into his possession, the purchaser acquires the merchandise being sold.

הלכה ח
זֶה שֶׁכּוֹתְבִין בִּשְׁטָרוֹת וְקָנִינָא מִפְּלוֹנִי בִּכְלִי הַכָּשֵׁר לִקְנוֹת בּוֹ. בִּכְלִי לְהוֹצִיא פֵּרוֹת וְכַיּוֹצֵא בָּהֶן. הַכָּשֵׁר לְהוֹצִיא אִסּוּרֵי הֲנָאָה. לִקְנוֹת בּוֹ לְהוֹצִיא כֶּלְיוֹ שֶׁל מוֹכֵר:
כסף משנה
8.
The above concepts are reflected in the expression used in legal documents: "And we performed a kinyan with so and so with a utensil that is acceptable to be used to conduct a transaction."
"A utensil" excludes produce and the like. "That is acceptable" excludes objects from which it is forbidden to benefit. And "to be used to conduct a transaction" excludes a utensil belonging to the seller.

הלכה ט
זֶה הַקִּנְיָן אֵין צָרִיךְ לִהְיוֹת בִּפְנֵי עֵדִים. אֶלָּא אִם הָיָה בֵּינוֹ וּבֵין חֲבֵרוֹ קָנָה. שֶׁלֹּא הִצְרִיכָה תּוֹרָה עֵדִים בְּדִינֵי מָמוֹנוֹת אֶלָּא לְכוֹפֵר. אֲבָל הַמּוֹכֵר אוֹ הַנּוֹתֵן אוֹ הַשּׂוֹכֵר אוֹ הַמַּשְׁאִיל וְכַיּוֹצֵא בָּהֶן אֵין צָרִיךְ עֵדִים. וְכֵיוָן שֶׁקָּנָה הַקּוֹנֶה בְּדֶרֶךְ אֶחָד מִן הַדְּרָכִים שֶׁקּוֹנִין בָּהֶן. בֵּין בְּהַגְבָּהָה. בֵּין בִּמְשִׁיכָה. בֵּין בִּמְסִירָה. בֵּין בְּקִנְיָן. בֵּין בְּכֶסֶף. בֵּין בִּשְׁטָר אוֹ בַּחֲזָקָה קָנָה. וְאַף עַל פִּי שֶׁאֵין שָׁם עֵדִים:
כסף משנה
9.
This transaction need not be performed in the presence of witnesses. Instead, even if it was performed only in the presence of the seller and the purchaser, the transaction is finalized. For the only reason the Torah required witnesses with regard to monetary laws is to prevent a person from denying what transpired.
A seller, one who gives a gift, rents out an object, lends an object or the like does not require witnesses. Whenever the second party finalizes the transaction through one of the accepted practices - lifting the article up, meshichah, transferring it, chalifin, the payment of money, the transfer of a legal document or through manifesting ownership - the transaction is concluded, even when there are no witnesses present.

הלכה י
הַמּוֹכֵר אוֹ הַנּוֹתֵן שֶׁקָּנוּ מִיָּדוֹ יֵשׁ לְכָל אֶחָד מֵהֶן לַחְזֹר בּוֹ כָּל זְמַן שֶׁעוֹסְקִין בְּאוֹתוֹ עִנְיָן. וְאַף עַל פִּי שֶׁהַקִּנְיָן בִּפְנֵי עֵדִים. וְאִם הִפְסִיק הָעִנְיָן אֵין אֶחָד מֵהֶם יָכוֹל לַחְזֹר אַף עַל פִּי שֶׁאֵין בֵּינֵיהֶן עֵדִים. וּכְשֵׁם שֶׁחוֹזֵר הַמּוֹכֵר וְהַנּוֹתֵן כָּךְ חוֹזֵר הַלּוֹקֵחַ וְהַמְקַבֵּל כָּל זְמַן שֶׁעֲסוּקִין בְּאוֹתוֹ עִנְיַן מַה שֶּׁאֵין כֵּן בִּשְׁאָר דַּרְכֵי הַקְּנִיָּה:
כסף משנה
10.
Although a person who sells or gives an article confirms the transaction with a kinyan chalifin, both of them may retract as long as they are discussing the matter. This applies even when the kinyan was performed in the presence of witnesses. If they concluded discussing the matter, neither may retract even though the transaction was not observed by witnesses.
Just as the seller and the giver may retract, so too, the purchaser and the recipient may retract as long as they are discussing the matter. This leniency does not apply with regard to other kinyanim.

הלכה יא
יֵשׁ דְּבָרִים הַרְבֵּה שֶׁאֵינָן צְרִיכִין קִנְיָן וְאֵין לְקִנְיָן בָּהֶם טַעַם. כְּגוֹן הַמְשַׁחְרֵר אֶת עַבְדּוֹ. וְהַמְגָרֵשׁ אִשְׁתּוֹ. אוֹ עוֹשֶׂה שָׁלִיחַ. אוֹ הַמּוֹסֵר מוֹדָעָה. אוֹ הַמְבַטֵּל מוֹדָעָה. אוֹ הַמּוֹחֵל לַחֲבֵרוֹ חוֹב אוֹ פִּקָּדוֹן שֶׁיֵּשׁ לוֹ בְּיָדוֹ. וְכָל כַּיּוֹצֵא בִּדְבָרִים אֵלּוּ:
כסף משנה
11.
There are many matters that do not require a kinyan, and indeed there is no reason to perform a kinyan with regard to them - e.g., a person who frees his slave, divorces his wife, appoints an agent, issues a protest with regard to a sale, nullifies a protest or waives a colleague's obligation to pay a debt or return an entrusted object. Similar laws apply to other analogous situations.

הלכה יב
נָהֲגוּ רֹב הַמְּקוֹמוֹת לְהַקְנוֹת לְמִקְצָת אֵלּוּ הַדְּבָרִים אוֹ כַּיּוֹצֵא בְּאֵלּוּ. וְאוֹמְרִים וְקָנִינוּ מִפְּלוֹנִי שֶׁעָשָׂה פְּלוֹנִי שָׁלִיחַ. אוֹ שֶׁמָּחַל לִפְלוֹנִי חוֹב שֶׁיֵּשׁ לוֹ אֶצְלוֹ. אוֹ שֶׁבִּטֵּל הַמּוֹדָעָה שֶׁמָּסַר עַל גֵּט זֶה וְכַיּוֹצֵא בְּאֵלּוּ. אַף עַל פִּי שֶׁאֵינוֹ צָרִיךְ:
כסף משנה
12.
It has become customary in the majority of places to perform a kinyan to confirm certain of the above matters and the like, even though it is not necessary. The witnesses say: "We performed a kinyan with so and so, confirming that he appointed so and so as an agent," "...waived the debt that so and so owed him," or "...nullified the protest he had issued concerning this bill of divorce," or the like.

הלכה יג
קִנְיָן זֶה שֶׁנָּהֲגוּ לְהַקְנוֹת בְּאֵלּוּ הַדְּבָרִים אֵינוֹ מוֹעִיל כְּלוּם. אֶלָּא לְהוֹדִיעַ שֶׁאֵינוֹ אוֹמֵר דְּבָרִים אֵלּוּ כִּמְשַׂחֵק וּמְהַתֵּל אֶלָּא שֶׁגָּמַר בְּלִבּוֹ וְאַחַר כָּךְ אָמַר. לְפִיכָךְ אִם אָמַר בְּלֵב שָׁלֵם אֲנִי אָמַרְתִּי וְגָמַרְתִּי לַעֲשׂוֹת דָּבָר זֶה אֵין צָרִיךְ דָּבָר אַחֵר כְּלָל:
כסף משנה
13.
Such a kinyan, which is customarily performed with regard to these matters, is of no consequence except to demonstrate that the parties involved were not acting facetiously or in jest when making the statements, but had in fact made a resolution in their hearts before making the statements. Therefore, if a person says: "I am making my statements with a full heart, and I have resolved to do this," nothing else is necessary.

הלכה יד
הַדְּבָרִים שֶׁאֵין בָּהֶן מַמָּשׁ אֵין הַקִּנְיָן מוֹעִיל בָּהֶן. כֵּיצַד. הֲרֵי שֶׁכָּתַב בִּשְׁטָר וְקָנִינוּ מִפְּלוֹנִי שֶׁיֵּלֵךְ בִּסְחוֹרָה עִם פְּלוֹנִי. אוֹ שֶׁיַּחְלְקוּ הַשָּׂדֶה שֶׁבֵּינֵיהֶם. אוֹ שֶׁיִּשְׁתַּתְּפוּ שְׁנֵיהֶם בְּאֻמָּנוּת. וְכַיּוֹצֵא בִּדְבָרִים אֵלּוּ כֻּלָּן. הֲרֵי זֶה קִנְיַן דְּבָרִים וְאֵינוֹ מוֹעִיל כְּלוּם. שֶׁהֲרֵי לֹא הִקְנָה לַחֲבֵרוֹ דָּבָר מְסֻיָּם וְיָדוּעַ. לֹא עִקָּר וְלֹא פֵּרוֹת עִקָּר הַיָּדוּעַ:
כסף משנה
14.
A kinyan is of no consequence with regard to statements that are of no substance.
What is implied? If it is stated in a legal document: "We performed a kinyan with so and so, confirming that he will travel to sell merchandise with so and so," "...that they will form a craft partnership," "...that they will divide a field between themselves," or the like, this is considered a kinyan with regard to words, and it is of no consequence. The rationale is that the person did not transfer to his colleague a specific and known entity, neither the entity itself or the fruits of that known entity.

קניין הלכות מכירה פרק ה
Kinyan Mechirah Chapter 5