كتاب التوبة
50
The Book of Repentance
(2)
Chapter: Sins Are Erased By Praying For Forgiveness And Repenting
(2)
باب سُقُوطِ الذُّنُوبِ بِالاِسْتِغْفَارِ تَوْبَةً ‏‏

Abu Huraira reported Allah's Messenger (ﷺ) having said:

By Him in Whose Hand is my life, if you were not to commit sin, Allah would sweep you out of existence and He would replace (you by) those people who would commit sin and seek forgiveness from Allah, and He would have pardoned them.
حَدَّثَنِي مُحَمَّدُ بْنُ رَافِعٍ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ، أَخْبَرَنَا مَعْمَرٌ، عَنْ جَعْفَرٍ الْجَزَرِيِّ، عَنْ يَزِيدَ بْنِ الأَصَمِّ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ "‏ وَالَّذِي نَفْسِي بِيَدِهِ لَوْ لَمْ تُذْنِبُوا لَذَهَبَ اللَّهُ بِكُمْ وَلَجَاءَ بِقَوْمٍ يُذْنِبُونَ فَيَسْتَغْفِرُونَ اللَّهَ فَيَغْفِرُ لَهُمْ ‏"‏ ‏.‏
Reference : Sahih Muslim 2749
In-book reference : Book 50, Hadith 13
USC-MSA web (English) reference : Book 37, Hadith 6622
  (deprecated numbering scheme)