Sahih Muslim 2590
Sahih Muslim · Book 45: The Book of Virtue, Enjoining Good Manners, and Joining of the Ties of Kinship · Glad Tidings That Whomever Allah Conceals In This World He Will Conceal Him In The Hereafter
Abu Huraira reported Allah's Apostle (ﷺ) as saying:
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ ، حَدَّثَنَا عَفَّانُ ، حَدَّثَنَا وُهَيْبٌ ، حَدَّثَنَا سُهَيْلٌ ، عَنْ أَبِيهِ ، عَنْ أَبِي هُرَيْرَةَ ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " لاَ يَسْتُرُ عَبْدٌ عَبْدًا فِي الدُّنْيَا إِلاَّ سَتَرَهُ اللَّهُ يَوْمَ الْقِيَامَةِ " .
The servant (who conceals) the faults of others in this world, Allah would conceal his faults on the Day of Resurrection.