Sahih al-Bukhari, Volume 8, Book 73, Hadith 95 (USC-MSA) ⓘ

Narrated Abu Huraira: I heard Allah's Messenger saying. "All the sins of my followers will be forgiven except those of the Mujahirin (those who commit a sin openly or disclose their sins to the people). An example of such disclosure is that a person commits a sin at night and though Allah screens it from the public, then he comes in the morning, and says, 'O so-and-so, I did such-and-such (evil) deed yesterday,' though he spent his night screened by his Lord (none knowing about his sin) and in the morning he removes Allah's screen from himself."

حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا إِبْرَاهِيمُ بْنُ سَعْدٍ، عَنِ ابْنِ أَخِي ابْنِ شِهَابٍ، عَنِ ابْنِ شِهَابٍ، عَنْ سَالِمِ بْنِ عَبْدِ اللَّهِ، قَالَ سَمِعْتُ أَبَا هُرَيْرَةَ، يَقُولُ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ ‏ "‏ كُلُّ أُمَّتِي مُعَافًى إِلاَّ الْمُجَاهِرِينَ، وَإِنَّ مِنَ الْمَجَانَةِ أَنْ يَعْمَلَ الرَّجُلُ بِاللَّيْلِ عَمَلاً، ثُمَّ يُصْبِحَ وَقَدْ سَتَرَهُ اللَّهُ، فَيَقُولَ يَا فُلاَنُ عَمِلْتُ الْبَارِحَةَ كَذَا وَكَذَا، وَقَدْ بَاتَ يَسْتُرُهُ رَبُّهُ وَيُصْبِحُ يَكْشِفُ سِتْرَ اللَّهِ عَنْهُ ‏" ‏‏.‏