I am not the most organized person and often I run out of supplies when preparing a meal. As a result, I borrow food from my neighbor. Is there any problem of ribbis if I return a little more? For example, I sometimes borrow eggs and I might borrow a medium size egg and, since I like to buy large eggs, I’ll return large eggs because that is what I have available to return. Similarly, sometimes I borrow potatoes and generally, I return a larger potato because I don’t want to return less and it is impossible to return the exact same size since every potato is different. I always thought that it is permitted because the reason I return more is not because of a loan but just out of convenience and honesty but then my son came home one day from yeshiva and told me I’m wrong. Was my thinking correct or is my son right?
First, it is necessary to lay some groundwork. The ribbis prohibited by the Torah is known as ribbis ketsutso. This occurs when the parties agree at the time the loan is granted that the borrower will return more than he borrowed. The Rabbonon extended this issur to many more situations.
One of the extensions is that the Rabbonon forbade lending all goods – meaning anything that is not money – because the price might change in the interim. This issur is known as so’o beso’o. Literally, it means that one is not allowed to borrow a measure of grain even to return the exact same measure as he borrowed. The Chachomim feared that in the interim the price of grain may rise and if the price rose, the borrower will effectively return more than he borrowed since the monetary value of what he returned was greater than the monetary value of what he borrowed. The Rabbonon allowed loans of goods only if either the borrower already has some of the item he is borrowing, or the goods are available for purchase at a price which doesn’t fluctuate. However, if neither of these is the case one may not lend out goods.
Concerning neighbors, the Mishna (Bava Metsiyo 75A) cites the opinion of Hillel that a woman may not lend a loaf of bread to her friend unless they appraise the loaf and set the loan such that the borrower is required to return the value of the loaf and not a loaf. The reason of Hillel is that otherwise this is an example of borrowing a measure for a measure which is the prohibition of lending a so’o beso’o. The Gemara writes that the Chachomim disagreed with Hillel and maintained that it is permitted. We should note that the Rama (Yoreh Deiah 162, 1) rules according to the view of the Chachomim. He writes that the reason is because it is not frequent that the price jump is significant.
The Shulchan Aruch (Yoreh Deiah 160, 17), based on another Gemara, permits talmidei chachomim to lend each other even 100 items of food for 120 (but not more) of that same item. This leniency is restricted to a situation in which both the lender and the borrower are talmidei chachomim. The reason for this leniency is that we are certain that the extra amount is given as a present and is not part of the loan. We must note that the talmid chacham included in this leniency is only one who is especially G-d fearing and would certainly not give or take interest.
When dealing with non-talmidei chachomim the entire discussion until now was whether it is permitted to lend and pay back the same amount. Your question, however, concerns giving back a slightly larger amount that isn’t very noticeable. However, this can be derived (proof of Divrei Sofrim –(Eimeik Dovor 162, 66)) from the Rashbo’s commentary to this section of Gemoro (Shabbos 148B). He writes that the loaves that the Gemara was discussing were home baked and their size was not uniform. He explains that even Hillel was only concerned that perhaps the price of a loaf would increase in the interim but not that the size of the loaf that the borrower returns may be slightly larger than the one he borrowed. The reason is because this difference does not translate into a difference in price. Thus, we can derive that one may borrow from a neighbor items which are not uniform even if in the end the borrower returns a slightly larger object.
The Bris Yehuda (17, footnote 6) and Toras Haribis (7, BH 7) also tend to think that it is permitted. They derive this from the reason that is given by the Ramo, that the difference in value is not significant. They contend that if this is the reason for the leniency to borrow goods then similarly when the difference in size is not significant it is permitted even to return a slightly larger object. For example the Toras Haribis argues that the fact that people don’t weigh apples when they lend them indicates that they don’t attach any significance to slight variations in size, weight or price. The only reason we required a special leniency for talmidei chachomim is because there the difference was quite tangible and significant since it was a twenty percent difference. But where it is hardly noticeable even non-talmidei chachomim may borrow and pay back a slightly larger amount.
The Lehoros Nosson (6, 76) specifically discusses your reason for returning a slightly larger potato because you don’t want to return too little and be guilty of theft. He permits this, citing an Avnei Nezer (Choshen Mishpot 23) that if one is uncertain if he already returned what he borrowed, he may, out of doubt, give the amount to the lender even though it is possible that he will be returning twice the amount that he borrowed, since his reason for doing so is the desire to avoid aveiros and not to return a favor to the one who lent him.
The Toras Haribis hesitates at permitting one to return larger sizes of eggs since eggs are classified based on size. Therefore, he would not permit one who borrowed a medium egg to return a large egg.
We should note that our entire discussion was in case the neighbors lent to each other. However, if the neighbor who gives something states clearly that he doesn’t mind if his neighbor never returns the item he received from him, there is altogether no problem since no loan ever took place. One could argue that generally for small amounts like an egg or a cup of sugar even if nothing was said, that is the intention. This probably also depends on the type of relationship the neighbors have. In any case, to be safe it is best if the lender states clearly that he doesn’t mind if the borrower fails to return what he received since that will avoid any danger of violating the prohibition of ribis.
In conclusion: It is best if those who lend you tell you that you are not required to return anything since then there is no loan and you can return more than what you borrowed. If they don’t wish to do so, you may pay back slightly larger potatoes if you are doing so because you don’t want to return less than the amount you borrowed. However, you should not return a larger class of eggs.