كتاب صفة القيامة والجنة والنار
52  
Characteristics of the Day of Judgment, Paradise, and Hell
(17)
Chapter: No One Will Enter Paradise By Virtue Of His Deeds, Rather By The Mercy Of Allah, Exalted Is He
(17)
باب لَنْ يَدْخُلَ أَحَدٌ الْجَنَّةَ بِعَمَلِهِ بَلْ بِرَحْمَةِ اللَّهِ تَعَالَى ‏‏
Sahih Muslim 2816 c

Abu Huraira reported Allah's Messenger (ﷺ) as saying:

There is none whose deeds alone would entitle him to get into Paradise. It was said to him: And, Allah's Messenger, not even you? Thereupon he said: Not even I, but that my Lord wraps me in Mercy.
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا حَمَّادٌ، - يَعْنِي ابْنَ زَيْدٍ - عَنْ أَيُّوبَ، عَنْ مُحَمَّدٍ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم قَالَ ‏"‏ مَا مِنْ أَحَدٍ يُدْخِلُهُ عَمَلُهُ الْجَنَّةَ ‏"‏ ‏.‏ فَقِيلَ وَلاَ أَنْتَ يَا رَسُولَ اللَّهِ قَالَ ‏"‏ وَلاَ أَنَا إِلاَّ أَنْ يَتَغَمَّدَنِي رَبِّي بِرَحْمَةٍ ‏"‏ ‏.‏
Reference : Sahih Muslim 2816c
In-book reference : Book 52, Hadith 66
USC-MSA web (English) reference : Book 39, Hadith 6761
  (deprecated numbering scheme)