הַמַּלְוֶה אֶת חֲבֵרוֹ סֶלַע בַּחֲמִשָּׁה דִּינָרִים אוֹ סָאתַיִם חִטִּים בְּשָׁלֹשׁ אוֹ סֶלַע בְּסֶלַע וּסְאָה אוֹ שָׁלֹשׁ סְאִין בְּשָׁלֹשׁ סְאִין וְדִינָר כְּלָלוֹ שֶׁל דָּבָר כָּל הַלְוָאָה בְּתוֹסֶפֶת כָּל שֶׁהוּא הֲרֵי זוֹ רִבִּית שֶׁל תּוֹרָה וְיוֹצְאָה בְּדַיָּנִין. וְכֵן הַמַּלְוֶה אֶת חֲבֵרוֹ וְהִתְנָה עִמּוֹ שֶׁיָּדוּר בַּחֲצֵרוֹ חִנָּם עַד שֶׁיַּחְזִיר לוֹ הַלְוָאָתוֹ. אוֹ שֶׁשָּׂכַר מִמֶּנּוּ בְּפָחוֹת וְקָצַב הַדָּבָר שֶׁפּוֹחֵת לוֹ מִן הַשָּׂכָר עַד שֶׁיַּחְזִיר לוֹ הַלְוָאָתוֹ. אוֹ שֶׁמִּשְׁכֵּן בְּיָדוֹ מָקוֹם שֶׁפֵּרוֹתָיו מְצוּיִין בְּעֵת הַהַלְוָאָה כְּגוֹן שֶׁמִּשְׁכֵּן חֲצֵרוֹ עַל מְנָת שֶׁיָּדוּר בּוֹ בְּחִנָּם. הֲרֵי זוֹ רִבִּית שֶׁל תּוֹרָה וְיוֹצְאָה בְּדַיָּנִין. וְכֵן הַמּוֹכֵר שָׂדֶה אוֹ חָצֵר בְּאַסְמַכְתָּא הוֹאִיל וְלֹא קָנָה הַגּוּף הֲרֵי כָּל הַפֵּרוֹת שֶׁאָכַל רִבִּית וּמַחֲזִיר אוֹתָן. וְהוּא הַדִּין לְכָל מִי [שֶׁלֹּא] קָנָה קִנְיָן גָּמוּר מִתְּחִלָּה שֶׁהוּא מַחְזִיר אֶת הַפֵּרוֹת מִפְּנֵי שֶׁאִם אָכַל אֶת הַפֵּרוֹת הֲרֵי זוֹ רִבִּית שֶׁל תּוֹרָה. וְכָל דָּבָר שֶׁהוּא אָסוּר מִשּׁוּם רִבִּית חוּץ מֵאֵלּוּ הֲרֵי הוּא אָסוּר מִדִּבְרֵיהֶם גְּזֵרָה שֶׁמָּא יָבֹא לְרִבִּית שֶׁל תּוֹרָה. וְהוּא הַנִּקְרָא אֲבַק רִבִּית וְאֵינוֹ יוֹצֵא בְּדַיָּנִין:
Whenever a person gives a loan to a colleague of a sela for five dinarim, two se'ah of wheat for three, a selah for a selah and a se'ah or three se'ah for three se'ah and a dinar, it is forbidden. The general principle is whenever there is a stipulation that any increase be made to a loan, interest forbidden by Scriptural Law is involved, and it may be expropriated from the lender through legal process. Similarly, when a person lends money to a colleague and makes a stipulation that he can live in the borrower's courtyard at no cost until he returns the loan, he rented the borrower's property for less than its fair value and established that this reduction would remain in force until he repaid the debt, or took as security property from which benefit can be derived at the time of the loan - e.g., the borrower gave the lender his courtyard as security with the intent that the lender dwell in it without charge - all the above are forms of interest forbidden by Scriptural Law and it may be expropriated from the lender through legal process. Similarly, when a person sells a field or a courtyard through an asmachta, since the purchaser does not acquire the field itself, any produce that he consumes is interest and must be returned. Similar laws apply to any person who has not completed a transaction that is not fully binding at the outset. He must return all the produce. For if he consumes the produce, he will be taking interest according to Scriptural Law. Any other matter forbidden as interest outside the above categories is prohibited by Rabbinic decree. These decrees were enforced lest this lead to the violation of interest forbidden by Scriptural Law. Interest forbidden by the Rabbis is called "the shade of interest" and may not be expropriated from the lender through legal process.
