Q: My neighbor went away and asked me to watch his expensive lawn mower, which I put in the garage. I took the liberty of using it without permission for my own lawn. Am I liable if it was subsequently stolen?

A: One of the guardian’s oaths is that he did not misappropriate the entrusted item. If he took it with intention to steal it (shelichus yad), he becomes fully liable - even for loss through uncontrollable circumstances (oness) - until he informs the owner that he took the item and returned it (C.M. 353:3).

The same is true if the guardian took the item with the intention to use it in a manner that causes wear on it or detracts from its value (292:1). If the guardian took the item to use in a manner that does not detract from its value, he is called sho’el shelo midaas (borrower without permission), which is also considered a form of theft. He becomes liable from the time he actually uses it.

The Rema exempts him after he returns the item to its place, but many later authorities dispute this ruling or limit it to situations where the owner would have allowed usage (292:1; Sm”a 292:4; Shach 292:1).

Iy”H, next week we will discuss circumstances in which usage might be permitted.