Sahih Ibn Khuzaymah

And the explanation that Allah Almighty accepts charity and nurtures it for the one who gives charity. And the explanation that Allah Almighty accepts charity only from pure wealth.

Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: "Whenever a Muslim man gives charity from his lawful and pure earnings—and Allah accepts only charity given from lawful wealth—then Allah takes that charity in His right hand and nurtures it just as one of you nurtures his foal, or he said, his calf, until even a single date (given in charity) becomes as large as the mountain of Uhud." Janab Utbah says that the meaning of "faluwahu" is a foal, and I did not record the words "as large as Uhud" in the narration of Janab Uqbah.

Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: "When a servant gives charity from his lawful and pure earnings, Allah accepts it and takes it in His right hand, and nurtures it just as one of you nurtures his foal or calf. Indeed, a person gives charity of a single morsel, and it is nurtured in the hand of Allah—or he said: 'in the palm of Allah'—until it becomes like a mountain. Therefore, give charity."

Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said, as narrated in the hadith of ‘Abdur Razzaq. There is an addition in the narration of Ja‘far that its confirmation is also in the Book of Allah « يَمْحَقُ اللَّهُ الرِّبَا وَيُرْبِي الصَّدَقَاتِ » [ سورة البقرة : 276 ] “Allah destroys usury and increases charity.”