Musnad Ahmad 1007:140

Yahya ibn Abi Kathir said, and Abdullah ibn Abi Talha narrated to me, that the Prophet, may Allah bless him and grant him peace, said: "If one of you eats, let him not eat with his left hand, and if he drinks, let him not drink with his left hand. And if he takes, let him not take with his left hand, and if he gives, let him not give with his left hand."