Bukhari Collection: ::Book Number 3:: Hadith # 777
Narrated Abu Huraira:Allah's Apostle owed a man some debt (and that man demanded it very harshly). The companions of the Prophet wanted to harm him, but the Prophet said to them, "Leave him, as the creditor has the right to speak harshly." He then added, "Buy (a camel) of the same age and give it to him." They said, "We cannot get except a camel of an older age than that of his." He said, "Buy it and give it to him, as the best amongst you is he who pays back his debt in the most handsome way.'