Musnad Ahmad 28:452

Yazid ibn Harun and Muhammad ibn Yazid narrated to us, they said: Muhammad ibn Ishaq informed us, from ‘Amr ibn Shu‘ayb, from his father, from his grandfather, who said: I said: "O Messenger of Allah, shall I write down what I hear from you?" He said: "Yes." I said: "In times of contentment and anger?" He said: "Yes, for it is not appropriate for me to say anything regarding that except the truth." Muhammad ibn Yazid said in his narration: "O Messenger of Allah, I hear things from you, so shall I write them down?" He said: "Yes."