Sayyiduna Abu Barzah al-Aslami (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) said: "A servant gives a morsel in charity, and it keeps growing in the presence of Allah Almighty until it becomes like the mountain of Uhud."
Al-Tabarani recorded it in al-Mu'jam al-Kabir. Its chain contains a narrator, Sawwar bin Mus'ab, and he is da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الزكاة / 4615