The Messenger of Allah ﷺ said, "There is no believing servant who gives a charity from pure earnings, and Allah accepts only what is pure, and only what is pure ascends to the heavens, except that He places it in the hand of the Most Merciful, where He nurtures it for him just as one of you nurtures his colt or young camel, until even a single date becomes like a great mountain."
حدثنا قتيبة حدثنا بكر بن مضر عن ابن عجلان أن سعيد بن يسار أبا الحباب أخبره
أن رسول الله ﷺ قال ما من عبد مؤمن تصدق بصدقة من طيب ولا يقبل الله إلا طيبا ولا يصعد السماء إلا طيب إلا وهو يضعها في يد الرحمن أو في كف الرحمن فيربيها له كما يربي أحدكم فلوه أو فصيله حتى إن التمرة لتكون مثل الجبل العظيم
Its isnad is sahih. Muslim reported it, 2/702, no. 1014, in the chapter on zakat, on accepting charity from wholesome earnings, and Tirmidhi, 3/40, no. 661, in the chapter on zakat, on what has been said regarding the merit of charity, and he said, hasan sahih.