Musnad Ahmad 30:2703

Hajjaj and Yunus narrated to us, they said: Layth narrated to us, he said: Bukayr narrated to me, from Busr ibn Sa'id, from Abu Hurayrah, from the Messenger of Allah, may Allah bless him and grant him peace, that he said: "None of you will be saved by his deeds." A man said: "Not even you, O Messenger of Allah?" He said: "Not even me, unless Allah covers me with His mercy. But strive for correctness."