It is narrated from Abu Hurairah (may Allah be pleased with him) that he reports: I heard Abul Qasim ﷺ saying, "By Him in Whose hand is my soul! Whoever gives charity from lawful earnings—and Allah accepts only what is lawful—and only charity from lawful earnings reaches Allah. It is as if someone places it in the hand of the Most Merciful, then He (Allah) increases it for the giver, just as one of you raises his young animal by feeding and nurturing it, until a single morsel becomes as great as a huge mountain on the Day of Resurrection." Then the Prophet ﷺ recited this verse: "Allah is the One Who accepts repentance from His servants and accepts charities." (__QUR_N__ at-Tawbah: 104)
Hadith Referenceمسند الإمام الشافعي / كتاب الزكاة / 686
Hadith Takhrijاخرجه البخارى، الزكاة، باب الصدقة، من كسب طيب لقوله ويربي الصدقات ..... الخ ) (1410) ۔ ومسلم، الزكاة، باب قبول الصدقة من الكسب الطيب وتربيتها (1014)۔