Musnad Ahmad 1060:91

Hassan narrated to us, Shu'bah narrated to us, from Muhammad ibn 'Abd al-Rahman ibn Abi Layla, from his brother—and he said: I have seen his brother—from his father, from Abu Ayyub, from the Prophet, may Allah bless him and grant him peace, and he mentioned the like of it, except that he said: "And let him say: 'May Allah guide you and rectify your state,'" or he said: "May Allah guide you [plural] and rectify your state [plural]."