كتاب التوبة
50  
The Book of Repentance
(8)
Chapter: The Acceptance Of The Repentance Of The One Who Kills, Even If He Has Killed A Great Deal
(8)
باب قَبُولِ تَوْبَةِ الْقَاتِلِ وَإِنْ كَثُرَ قَتْلُهُ ‏‏
Sahih Muslim 2768

Safwan b. Muhriz reported that a person said to Ibn 'Umar:

How did you hear Allah's Messenger (ﷺ) as saying something about intimate conversation? He said: I heard him say: A believer will be brought to his Lord, the Exalted and Glorious, on the Day of Resurrection and He would place upon him His veil (of Light) and make him confess his faults and say: Do you recognise (your faults)? He would say: My Lord, I do recognise (them). He (the Lord) would say: I concealed them for you in the world. And today I forgive them. And he would then be given the Book containing (the account of his) good deeds. And so far as the non-believers and hypocrites are concerned, there would be general announcement about them before all creation telling them that these (people, i. e. non-believers and hypocrites) told a lie about Allah.
حَدَّثَنَا زُهَيْرُ بْنُ حَرْبٍ، حَدَّثَنَا إِسْمَاعِيلُ بْنُ إِبْرَاهِيمَ، عَنْ هِشَامٍ الدَّسْتَوَائِيِّ، عَنْ قَتَادَةَ، عَنْ صَفْوَانَ بْنِ مُحْرِزٍ، قَالَ قَالَ رَجُلٌ لاِبْنِ عُمَرَ كَيْفَ سَمِعْتَ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ فِي النَّجْوَى قَالَ سَمِعْتُهُ يَقُولُ ‏ "‏ يُدْنَى الْمُؤْمِنُ يَوْمَ الْقِيَامَةِ مِنْ رَبِّهِ عَزَّ وَجَلَّ حَتَّى يَضَعَ عَلَيْهِ كَنَفَهُ فَيُقَرِّرُهُ بِذُنُوبِهِ فَيَقُولُ هَلْ تَعْرِفُ فَيَقُولُ أَىْ رَبِّ أَعْرِفُ ‏.‏ قَالَ فَإِنِّي قَدْ سَتَرْتُهَا عَلَيْكَ فِي الدُّنْيَا وَإِنِّي أَغْفِرُهَا لَكَ الْيَوْمَ ‏.‏ فَيُعْطَى صَحِيفَةَ حَسَنَاتِهِ وَأَمَّا الْكُفَّارُ وَالْمُنَافِقُونَ فَيُنَادَى بِهِمْ عَلَى رُءُوسِ الْخَلاَئِقِ هَؤُلاَءِ الَّذِينَ كَذَبُوا عَلَى اللَّهِ ‏"‏ ‏.‏
Reference : Sahih Muslim 2768
In-book reference : Book 50, Hadith 61
USC-MSA web (English) reference : Book 37, Hadith 6669
  (deprecated numbering scheme)