Sayyiduna Abu Hurayrah (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "Whoever spends the equivalent of a single date from pure earnings, and only what is pure (pure things) ascends to Allah, then Allah certainly accepts it with His right hand, then nurtures it for its owner, just as one of you nurtures his foal, until it becomes like the mountain of Uhud."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7838
It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever gives a single date in charity from pure earnings, Allah Almighty accepts it with His right hand and keeps nurturing it, just as one of you nurtures his foal, until it becomes like a mountain or even greater."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7839
Mus'ab bin Sa'd (may Allah have mercy on him) said: Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) went to visit Ibn Amir, who was ill, and he said: O Ibn Umar, will you not pray for me? Sayyiduna Ibn Umar (may Allah be pleased with them both) said: I heard the Messenger of Allah (peace and blessings be upon him) say: "No prayer is (accepted) without purification, and no charity is (accepted) from fraud (misappropriated wealth)," and you were (governor) over Basra.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7840