Halakhah for Bava Metzia 5:3
מָכַר לוֹ אֶת הַשָּׂדֶה, וְנָתַן לוֹ מִקְצָת דָּמִים, וְאָמַר לוֹ אֵימָתַי שֶׁתִּרְצֶה הָבֵא מָעוֹת וְטֹל אֶת שֶׁלְּךָ, אָסוּר. הִלְוָהוּ עַל שָׂדֵהוּ, וְאָמַר לוֹ, אִם אִי אַתָּה נוֹתֵן לִי מִכָּאן וְעַד שָׁלשׁ שָׁנִים הֲרֵי הִיא שֶׁלִּי, הֲרֵי הִיא שֶׁלּוֹ. וְכָךְ הָיָה בַּיְתוֹס בֶּן זוֹנִין עוֹשֶׂה עַל פִּי חֲכָמִים:
If he sold him the field and he gave him part of the money, and he (the seller) said to him: "When you wish, bring the (rest of the) money and take what is yours," this is forbidden. [As when the seller said to the buyer: "When you bring the rest of the money, acquire it from now." It is forbidden to do this, for if the seller eats fruits (of the field) in the interim, when the other brings the money, the field is found to have been acquired by him from the day of the sale, and the seller (is found) to have eaten fruits as payment for waiting. And if the buyer eats fruits from now, perhaps he will not bring the rest of the money and the seller will return what he had received from him, so that the field will be found not to have been sold to him (the seller having said: "When you bring the rest of the money, acquire it from now," and he did not bring it), and the first payment would be (found to have been) a loan in general to the buyer, and the seller would be found to have eaten fruits in payment (for having granted a loan)]. If he gave him a loan for his field, and he (the lender) said to him: "If you do not repay me from now until three years, it is mine," it is his. [As when he (the borrower) said to him: "Acquire it from now if I do not repay you from now until three years.," For this is not an asmachta (a mere "understanding"), but a bona fide kinyan (act of acquisition), the lender taking possession of it now for this money (that he gave the borrower), and it (the field) becomes cheaper in his (the lender's) possession. And the fruits are deposited with a third person. If the borrower repays the loan within three years, the fruits are given to him. And if not, they are given to the borrower, the field having been acquired by him from the time of the loan, and that loan having been payment for the field.] And Baitos b. Zonin did so (i.e., He borrowed upon his field) by the counsel of the sages.