Musnad Ahmad 30:469

Abu Kamil narrated to us, Ibrahim ibn Sa'd narrated to us, Ibn Shihab narrated to us, from Abu 'Ubayd, the freed slave of 'Abd al-Rahman ibn 'Awf, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "None of you will have his deeds cause him to enter Paradise." They said: "Not even you, O Messenger of Allah?" He said: "Not even me, unless Allah covers me with His favor and mercy."