Tha'labah bin Abi Su'ayr narrates from his father (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "A sa' of wheat is on behalf of two, whether they are young or old, free or slave, male or female. As for the one among you who is wealthy, Allah will purify him; and as for the one among you who is poor, He will return to him more than what he gave." [Da'if (weak). Its takhrij has preceded.]
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7709