Reference for Gittin 5:3
אֵין מוֹצִיאִין לַאֲכִילַת פֵּרוֹת וּלְשֶׁבַח קַרְקָעוֹת וְלִמְזוֹן הָאִשָּׁה וְהַבָּנוֹת מִנְּכָסִים מְשֻׁעְבָּדִים, מִפְּנֵי תִקּוּן הָעוֹלָם. וְהַמּוֹצֵא מְצִיאָה, לֹא יִשָּׁבַע, מִפְּנֵי תִקּוּן הָעוֹלָם:
Payment is not exacted for the eating of fruits, for the enrichment of land, and for the food of one's wife and daughters from bound property, for "the general good." [If one stole a field and sold it to another, and he sowed it and it sprouted and produced fruit, and the despoiled one came and claimed it with its fruit from the buyer (reimbursing him only for his expenses), the buyer returns and claims the price of the field from bound property, it having been sold to him with a guarantee by bill of sale, this being "a loan against a note" (milveh bishtar), and (he claims) the price of the fruit from free, and not from bound property. The same applies when the buyer enriched the land by planting trees or fertilizing it, and the like. ("and for the food of one's wife and daughters":) this being a condition of the kethubah, viz.: "And you shall dwell in my house and be fed through my property; and the daughters that you have by me will dwell in my house and be fed through my property, etc." When they come to claim their food, they do so only from free property, and not from bound property. ("for 'the general good'":) For these are indeterminate things and exact allowances cannot be made for them.] And if one found a lost object [and returned it, and the owner claimed that he did not return all of it], he does not take an oath, for "the general good." [For if an oath were imposed upon him, no one would take pains to return a lost object.]