Sahih Muslim
The Book Giving Description of the Day of Judgement, Paradise and Hell (Kitab Sifat Al-Qiyamah wal Janna wan-Nar)
Book Number: 039 / Hadith Number: 6765
Abu Huraira reported Allah's Messenger (may peace be upon him) as saying: Observe moderation in deeds (and if it is not possible, try to be near moderation) and understand that none amongst you can attain salvation because of his deeds alone. They said: Allah's Messenger, not even you? Thereupon he said: Not even I, but that Allah should wrap me in His Mercy and Grace.