Musnad Ahmad 547:7

Abu Abd al-Rahman said: I found this hadith in my father’s book in his own handwriting: Al-Rabi’ ibn Nafi’ Abu Tawbah wrote to me, and it was in his writing: Al-Haytham ibn Humayd narrated to us, from Zayd ibn Waqid, from Sulayman ibn Musa, from Kathir ibn Murrah, from Uqbah ibn Amir, who said: The Messenger of Allah, peace and blessings of Allah be upon him, said: "The one who recites the Quran quietly is like the one who gives charity quietly, and the one who recites the Quran aloud is like the one who gives charity aloud."