Abu Umama told of hearing God's Messenger say, “A loan must be paid back, a minha* must be returned, a debt must be discharged, and one who stands surety is held responsible.”
Tirmidhi and Abu Dawud transmitted it.
*This may be a she camel lent for a time for milking, but it can be used of other things which are lent for some specific purpose.
Umayya b. Safwan quoted his father as saying that at the battle of Hunain the Prophet borrowed his coats of mail and he asked, “Are you taking them by force, Muhammad ?” to which he replied, “No, it is a loan with a guarantee of their return.'’
When I was a boy I used to throw stones at the palm-trees belonging to the Ansar and was brought to the Prophet. He asked, “Why do you throw stones at the palm-trees, boy?” and when I replied that it was to get something to eat he said, “Do not' throw stones, but you may eat anything that falls below them.” Then passing his hand over my head he said, “O God, fill his belly.”