Musnad Ahmad 28:357

Isma'il ibn Ibrahim narrated to us, 'Ata' ibn al-Sa'ib narrated to us, from his father, from 'Abdullah ibn 'Amr, who said: A man came to the Prophet, may Allah bless him and grant him peace, and said: "I have come to pledge allegiance to you, and I have left my parents weeping." He said: "Return to them and make them laugh just as you made them weep," and he refused to accept his pledge.