Sa'id bin Abi Sa'id · The Book on Zakat

the Messenger of Allah said: "None gives charity from Tayyib - and Allah does not accept but Tayyib - but that Ar-Rahman accepts it with His Right (Hand). Even if it is a date, it is nurtured in the Hand of Ar-Rahman until it is greater than a mountain, just as one of you nurtures his foal or young camel."

Umm Bujaid - and she was one of those who gave the pledge to the Prophet - she said to the Messenger of Allah: "There is a needy person who stands outside my door, but I cannot find anything to give to him." So the Messenger of Allah said to her: "If you do not find anything to give him except a burnt trotter then hand it over to him."