[Machine] The Messenger of Allah ﷺ said, "Indeed, when a believer commits a sin, there is a black spot in his heart. If he repents, removes it, and seeks forgiveness, his heart is polished. But if he returns to sin, it increases until his heart is sealed with it. This is what Allah mentioned in His book, 'No! Rather, the stain has covered their hearts of that which they were earning' [Al-Mutaffifin 14]." The scholar mentioned that these narrations, along with those similar to them, serve as a warning and a reminder for those who persist in committing sins without seeking forgiveness and neglecting to repent from them.
أَنَّ رَسُولَ اللهِ ﷺ قَالَ إِنَّ الْمُؤْمِنَ إِذَا أَذْنَبَ ذَنْبًا كَانَتْ نُكْتَةٌ سَوْدَاءُ فِي قَلْبِهِ فَإِنْ تَابَ وَنَزَعَ وَاسْتَغْفَرَ صُقِلَ مِنْهَا قَلْبُهُ فَإِنْ عَادَ رَانَتْ حَتَّى يُغْلَقَ بِهَا قَلْبُهُ فَذَاكَ الَّذِي ذَكَرَ اللهُ ﷻ فِي كِتَابِهِ {كَلَّا بَلْ رَانَ عَلَى قُلُوبِهِمْ مَا كَانُوا يَكْسِبُونَ} [المطففين 14] قَالَ الشَّيْخُ وَيُشْبِهُ أَنْ تَكُونَ هَذِهِ الْأَخْبَارُ وَمَا جَانَسَهَا فِي التَّغْلِيظِ وَالتَّشْدِيدِ فِيمَنْ أَصَرَّ عَلَى الذُّنُوبِ غَيْرَ مُسْتَغْفِرٍ مِنْهَا وَلَا مُحَدِّثٍ نَفْسَهُ بِتَرْكِهَا