Musnad Abu Ya'la al-Mawsili 54:16

Ahmad ibn Ibrahim narrated to us, Abu Abd al-Rahman narrated to us, Sa'id narrated to us, Abu Marhum narrated to me, from Sahl ibn Mu'adh ibn Anas, from his father, that the Messenger of Allah (may Allah bless him and grant him peace) said: "Whoever eats food, then says: 'Praise be to Allah who fed me this food and provided it to me without any power or strength from me,' his past sins will be forgiven. And whoever wears a garment, then says: 'Praise be to Allah who clothed me with this and provided it to me without any power or strength from me,' his past sins will be forgiven."