Musannaf Ibn Abi Shayba 27:148

Muhammad ibn Fudayl narrated to us, from Yunus ibn ‘Amr, from Burayd ibn Abi Maryam, from Anas ibn Malik, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Whoever sends one blessing upon me, Allah will send ten blessings upon him and will remit ten of his sins."