Sayyiduna Abu Dharr al-Ghifari (may Allah be pleased with him) narrates: I said: O Messenger of Allah! What is charity? The Prophet (peace and blessings be upon him) said: Its reward is multiplied many times over. I said: O Messenger of Allah! Which of it is most virtuous? He said: The charity a person of little means gives through his own effort, or giving charity secretly to a poor person.
Ahmad recorded it within a long hadith. Its chain contains a narrator, Abu Amr al-Dimashqi, who is matruk (abandoned).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الزكاة / 4642