Musnad Ahmad 32:34

Ishaq ibn Yusuf al-Azraq narrated to us, Zakariya ibn Abi Za’idah narrated to us, from Sa’id ibn Abi Burdah, from Anas ibn Malik, who said: "I served the Prophet, may Allah bless him and grant him peace, for nine years. I do not know that he ever said to me: 'Why did you do such and such?' nor did he ever criticize anything I did."