Musnad Abu Ya'la al-Mawsili 115:151

Musa ibn Abd al-Rahman narrated to us, Umar ibn Sa'id al-Abbah narrated to us, from Sa'id, from Qatadah, from Anas, who said: I served the Messenger of Allah, may Allah bless him and grant him peace, for ten years. He never said to anything I did, "Why did you do it?" nor to anything I did not do, "Why did you not do it?"