Halacha

הלכה א
אָסוּר לַמּוֹכֵר לִמְכֹּר לַחֲבֵרוֹ קַרְקַע אוֹ מִטַּלִטְלִין שֶׁיֵּשׁ בָּהּ עֲסִיקִין וְיֵשׁ בָּהּ דִּין עַד שֶׁיּוֹדִיעוֹ. שֶׁאַף עַל פִּי שֶׁהָאַחֲרָיוּת עָלָיו אֵין אָדָם רוֹצֶה שֶׁיִּתֵּן מְעוֹתָיו וְיוֹרֵד לְדִין וְיִהְיֶה נִתְבָּע מֵאֲחֵרִים:
כסף משנה
1.
It is forbidden for a person to sell a colleague landed property or movable property concerning which there is a dispute or a judgment pending, until he notifies the purchaser. This law applies even if the seller is responsible for the property if it is expropriated from the purchaser. The rationale is that a person does not desire to pay money for an object and then be forced to enter into litigation concerning it, because he is being sued by others.

הלכה ב
הַמּוֹכֵר קַרְקַע לַחֲבֵרוֹ וְאַחַר שֶׁקָּנָה הַלּוֹקֵחַ בְּאֶחָד מִן הַדְּרָכִים שֶׁקּוֹנִין בָּהֶן קֹדֶם שֶׁיִּשְׁתַּמֵּשׁ בָּהּ יָצָא עָלָיו מְעַרְעֲרִין. הֲרֵי זֶה יָכוֹל לַחְזֹר בּוֹ. שֶׁאֵין לְךָ מוּם גָּדוֹל מִזֶּה שֶׁעֲדַיִן לֹא נֶהֱנָה בּוֹ וּבָאוּ הַתּוֹבְעִין. לְפִיכָךְ יִבָּטֵל הַמִּקָּח וְיַחְזִיר הַמּוֹכֵר אֶת הַדָּמִים וְיַעֲשֶׂה דִּין עִם הַמְעַרְעְרִין. וְאִם נִשְׁתַּמֵּשׁ בָּהּ הַלּוֹקֵחַ כָּל שֶׁהוּא וַאֲפִלּוּ דָּשׁ הַמֵּצַר שֶׁלָּהּ וְעֵרְבוֹ עִם הָאָרֶץ אֵינוֹ יָכוֹל לַחְזֹר בּוֹ אֶלָּא עוֹשֶׂה דִּין עִם הַמְעַרְעְרִין. וְאִם הוֹצִיאוּ מִיָּדוֹ בְּדִין יַחְזֹר עַל הַמּוֹכֵר כְּדִין כָּל הַנִּטְרָפִין:
כסף משנה
2.
When a person sells landed property to a colleague and claims of ownership are filed by others - after the purchaser acquires the property through one of the established modes of acquisition, but before he makes use of it - the purchaser may retract; there is no blemish greater than this. Before he has even made use of his purchase, claimants come and demand it.
Therefore, the transaction should be nullified and the seller should return the money and enter into litigation with the claimants. If the purchaser made any use of it whatsoever, even if he merely threw down its property marker and joined it to his own adjacent property, he may not retract. Instead, he must enter into litigation with the claimants. If they are successful in expropriating it from him in court, he may seek settlement from the seller, as is the law with regard to all from whom property is expropriated.

הלכה ג
כָּל הַמּוֹכֵר קַרְקַע אוֹ עֶבֶד אוֹ שְׁאָר מִטַּלְטְלִין הֲרֵי זֶה חַיָּב בְּאַחֲרָיוּתָן. כֵּיצַד. אִם הוֹצִיא הַמִּקָּח מִיַּד הַלּוֹקֵחַ מֵחֲמַת הַמּוֹכֵר. חוֹזֵר הַלּוֹקֵחַ וְנוֹטֵל כָּל הַדָּמִים שֶׁנָּתַן מִן הַמּוֹכֵר שֶׁהֲרֵי נִלְקָח הַמִּקָּח מֵחֲמָתוֹ. כָּךְ הַדִּין בְּכָל מִמְכָּר אַף עַל פִּי שֶׁלֹּא פֵּרֵשׁ הַלּוֹקֵחַ דָּבָר זֶה אֶלָּא קָנָה סְתָם. אֲפִלּוּ מָכַר הַקַּרְקַע בִּשְׁטָר וְלֹא הִזְכִּיר בּוֹ הָאַחֲרָיוּת הֲרֵי זֶה חַיָּב בְּאַחֲרָיוּתָן. שֶׁאַחֲרָיוּת שֶׁלֹּא נִזְכַּר טָעוּת סוֹפֵר הוּא:
כסף משנה
3.
Whenever a person sells landed property, a servant or other movable property, he is responsible for them. What is implied? If a litigant expropriates the purchased article from the purchaser because of the seller, the purchaser may collect all the money he paid from the seller, because the article was taken because of him.
This law applies with regard to all sales, even if the purchaser does not explicitly make this stipulation, but purchases the article without any qualification. Even if he purchases landed property by virtue of the transfer of a legal document, and the seller's responsibility is not mentioned in the document, the seller is responsible for the property. The fact that his responsibility is not mentioned is considered to be a scribal error.

הלכה ד
בַּמֶּה דְּבָרִים אֲמוּרִים כְּשֶׁהוֹצִיא הַמִּקָּח מִיַּד הַלּוֹקֵחַ בְּבֵית דִּין שֶׁל יִשְׂרָאֵל. כְּגוֹן שֶׁהָיָה הַמִּקָּח מִטַּלְטְלִין וְהָיוּ גְּנוּבִין אוֹ גְּזוּלִין אוֹ שֶׁהָיְתָה הַקַּרְקַע גְּזוּלָה. אוֹ שֶׁבָּא בַּעַל חוֹב שֶׁל מוֹכֵר וּטְרָפָהּ מִיַּד הַלּוֹקֵחַ וְהַכּל בְּבֵית דִּין שֶׁל יִשְׂרָאֵל. אֲבָל אִם הָעוֹבֵד כּוֹכָבִים הוּא שֶׁהוֹצִיא הַמִּקָּח מִן הַלּוֹקֵחַ בֵּין בְּדִין הַמֶּלֶךְ בֵּין בְּעַרְכָּאוֹת שֶׁלָּהֶן. אֵין הַמּוֹכֵר חַיָּב בְּאַחֲרָיוּתוֹ. וְאַף עַל פִּי שֶׁהָעוֹבֵד כּוֹכָבִים טוֹעֵן שֶׁהַמּוֹכֵר גָּנַב חֵפֶץ זֶה אוֹ גְּזָלָהּ מִמֶּנּוּ וְהֵבִיא עֵדֵי עַכּוּ''ם עַל כָּךְ אֵין הַמּוֹכֵר חַיָּב כְּלוּם. שֶׁזֶּה אֹנֶס הוּא וְאֵין הַמּוֹכֵר חַיָּב בְּאַחֲרָיוּת אֹנֶס:
כסף משנה
4.
When does the above apply? When the purchased article was expropriated from the purchaser in a Jewish court. For example, the purchased article was movable property and it was proven that it was obtained by theft or robbery, or landed property was taken by robbery, or a creditor of the seller came and expropriated it from the purchaser.
All the above applies if the expropriation was dictated by a Jewish court. If, however, a gentile expropriates the purchased article from the purchaser, whether through an edict of the king or through a secular court, the seller is not responsible for the article. Although the gentile claims that the seller stole this article or robbed him of it and brought witnesses to that effect, the seller is not liable at all. For the expropriation of the article by gentiles is considered to be beyond the seller's control, and a seller is not liable for losses that are beyond his control.

הלכה ה
הַמּוֹכֵר קַרְקַע לַחֲבֵרוֹ וְהִתְנָה עִמּוֹ שֶׁכָּל אֹנֶס שֶׁיִּוָּלֵד בְּקַרְקַע זֶה יִהְיֶה חַיָּב לְשַׁלֵּם. אֲפִלּוּ בָּא עַכּוּ''ם וּגְזָלָהּ מֵחֲמַת הַמּוֹכֵר חַיָּב לְשַׁלֵּם. אֲבָל אִם נִפְסַק הַנָּהָר שֶׁהָיָה מַשְׁקֶה אוֹתָהּ. אוֹ שֶׁחָזַר הַנָּהָר לַעֲבֹר בְּתוֹכָהּ וְנַעֲשֵׂית בְּרֵכָה. אוֹ שֶׁבָּאָה זְוָעָה וְהִשְׁחִיתָה אוֹתָהּ. הֲרֵי זֶה פָּטוּר. שֶׁאֵלּוּ וְכַיּוֹצֵא בָּהֶן אֹנֶס שֶׁאֵינוֹ מָצוּי הוּא וְלֹא עָלָה עַל לֵב הַמּוֹכֵר דְּבַר זֶה הַפֶּלֶא בְּעֵת שֶׁהִתְנָה. וְכָל אֹנֶס שֶׁאֵינוֹ מָצוּי אֵינוֹ בִּכְלַל הַתְּנַאי הַזֶּה:
כסף משנה
5.
When a person sells landed property to a colleague and the seller makes a stipulation that he will reimburse the purchaser for any loss of this property due to factors beyond his control, he is liable to pay even if a gentile comes and seizes by force the property due to the seller.
If, however, a stream that was watering the field dries up, the flow of a stream deviates and makes a portion of land into a pool, or an earthquake comes and destroys it, the seller is not liable. For matters of this nature are both beyond one's control and infrequent. It would not have occurred to a seller to think about such an abnormal matter at the time he made this stipulation. Similarly, any other factor beyond one's control that is abnormal is not included in this stipulation.

הלכה ו
וְהוּא הַדִּין לְכָל תְּנַאי מָמוֹן שֶׁאוֹמְדִין דַּעַת הַמַּתְנֶה וְאֵין כּוֹלְלִין בְּאוֹתוֹ הַתְּנַאי אֶלָּא דְּבָרִים הַיְדוּעִין שֶׁבִּכְלָלָן הָיָה הַתְּנַאי וְהֵם שֶׁהָיוּ בְּדַעַת הַמַּתְנֶה בִּשְׁעַת שֶׁהִתְנָה:
כסף משנה
6.
This same principle applies with regard to any condition that is made with regard to monetary matters. We analyze the intent of the person making the stipulation. We include within its scope only matters that are well-known that we would assume to have been taken in within the stipulation, because they would have been in the mind of the person making the stipulation at that time.

הלכה ז
מַעֲשֶׂה בְּאֶחָד שֶׁשָּׂכַר מַלָּחִים לְהָבִיא שֻׁמְשְׁמִין לְמָקוֹם פְּלוֹנִי. וְהִתְנָה עִמָּהֶם שֶׁהֵן חַיָּבִין בְּכָל אֹנֶס שֶׁיֶּאֱרַע לָהֶם עַד שֶׁיַּגִּיעוּ הַשֻּׁמְשְׁמִין לְמָקוֹם פְּלוֹנִי. וְנִפְסַק הַנָּהָר שֶׁהָיוּ מוֹלִיכִין בּוֹ. וְאָמְרוּ חֲכָמִים זֶה אֹנֶס שֶׁאֵינוֹ מָצוּי וְאֵין חַיָּבִין לְהוֹלִיךְ שֻׁמְשְׁמִין אֵלּוּ עַל גַּבֵּי בְּהֵמָה עַד אוֹתוֹ מָקוֹם. וְכֵן כָּל כַּיּוֹצֵא בָּזֶה:
כסף משנה
7.
An incident occurred concerning a person who hired sailors to transport sesame seeds to a certain place. He made a stipulation with them that they are responsible for any loss that occurs because of factors beyond their control until the sesame seeds reach their destination. And then, the river on which they expected to transport the cargo ceased flowing.
Our Sages said: This is an abnormal factor beyond their control. They are not likely to transport these sesame seeds on an animal to that place. Similar principles apply in all analogous situations.

הלכה ח
הַמּוֹכֵר קַרְקַע לַחֲבֵרוֹ וְהִתְנָה הַמּוֹכֵר שֶׁלֹּא יִהְיֶה עָלָיו אַחֲרָיוּת. אֲפִלּוּ נוֹדַע בְּוַדַּאי שֶׁזּוֹ הָאָרֶץ גְּזוּלָה וְיָצָאת מִיַּד הַלּוֹקֵחַ. אֵין הַמּוֹכֵר חַיָּב כְּלוּם. וְאֵין צָרִיךְ לוֹמַר אִם בָּא בַּעַל חוֹב וּטְרָפָהּ שֶׁאֵינוֹ מַחְזִיר לוֹ כְּלוּם. שֶׁכָּל תְּנַאי שֶׁבְּמָמוֹן קַיָּם:
כסף משנה
8.
When a person sells landed property to a colleague and the seller explicitly stipulates that he is not responsible, the seller is not held responsible. This applies even if it becomes known with certainty that the property was stolen, and it is expropriated from the purchaser.
Needless to say, should a creditor of the seller come and expropriate it from the purchaser, the seller is not liable to reimburse him. For any stipulation that is made with regard to financial matters is binding.

הלכה ט
רְאוּבֵן שֶׁמָּכַר שָׂדֶה לְשִׁמְעוֹן שֶׁלֹּא בְּאַחֲרָיוּת. וּבָא לֵוִי וְהוֹצִיאָהּ מִיַּד שִׁמְעוֹן. אִם רָצָה רְאוּבֵן לַעֲשׂוֹת דִּין עִם לֵוִי עוֹשֶׂה. וְאֵין יָכוֹל לֵוִי לוֹמַר לוֹ מַה לִּי וּלְךָ וַהֲרֵי אֵין עָלֶיךָ אַחֲרָיוּת. שֶׁהֲרֵי רְאוּבֵן אוֹמֵר לוֹ אֵין רְצוֹנִי שֶׁיִּהְיֶה לְשִׁמְעוֹן תַּרְעֹמֶת עָלַי שֶׁהֲרֵי הִפְסִיד בִּגְלָלִי:
כסף משנה
9.
The following rule applies when Reuven sold a field to Shimon without taking responsibility for it, and Levi comes and expropriates it from Shimon based on a claim against Reuven. If he desires, Reuven can enter into litigation with Levi. Levi cannot protest: "What business do you and I have together? You have no responsibility for the property." For Reuven will tell him: "I do not want Shimon to have any claims against me, for he has lost money on my account."

הלכה י
רְאוּבֵן שֶׁמָּכַר שָׂדֶה לְשִׁמְעוֹן שֶׁלֹּא בְּאַחֲרָיוּת וְחָזַר וּלְקָחָהּ מִשִּׁמְעוֹן בְּאַחֲרָיוּת. וּבָא בַּעַל חוֹב שֶׁל רְאוּבֵן לִטְרֹף אוֹתָהּ מִמֶּנּוּ. אֵינוֹ יָכוֹל לַחְזֹר עַל שִׁמְעוֹן. שֶׁאַף עַל פִּי שֶׁלֹּא קִבֵּל עָלָיו אַחֲרָיוּת לְשִׁמְעוֹן אַחֲרָיוּת עַצְמוֹ קִבֵּל שֶׁלֹּא יִהְיֶה הוּא הַמּוֹכֵר וְהוּא הַמּוֹצִיא לְעַצְמוֹ. אֲבָל אִם בָּא בַּעַל חוֹב שֶׁל יַעֲקֹב אֲבִיהֶם וּטְרָפָהּ מִיַּד רְאוּבֵן. חוֹזֵר בְּכָל הַדָּמִים עַל שִׁמְעוֹן. מִפְּנֵי שֶׁשִּׁמְעוֹן קִבֵּל לוֹ הָאַחֲרָיוּת וּרְאוּבֵן לֹא קִבֵּל לְשִׁמְעוֹן אַחֲרָיוּת שֶׁל אֲחֵרִים כְּלָל:
כסף משנה
10.
The following rule applies when Reuven sold a field to Shimon without taking responsibility and then repurchased it from him requiring Shimon to take responsibility. If a creditor of Reuven comes to expropriate the field from him, he may not require Shimon to pay for it. Although he did not accept responsibility when he sold it to Shimon, he took responsibility with regard to himself, that he should not be the seller and then expropriate the property himself.
If, however, a creditor of Jacob, their father, comes and expropriates the property from Reuven, Reuven may demand payment of the entire worth of the field from Shimon. For Shimon accepted responsibility for the field when he sold it back to Reuven, while Reuven did not accept any responsibility for others when he sold it to Shimon.

קניין הלכות מכירה פרק יט
Kinyan Mechirah Chapter 19