I heard the Messenger of Allah ﷺ say: There were two men among Banu Isra'il, who were striving for the same goal. One of them would commit sin and the other would strive to do his best in the world. The man who exerted himself in worship continued to see the other in sin. He would say: Refrain from it. One day he found him in sin and said to him: Refrain from it. He said: Leave me alone with my Lord. Have you been sent as a watchman over me? He said: I swear by Allah, Allah will not forgive you, nor will he admit you to Paradise. Then their souls were taken back (by Allah), and they met together with the Lord of the worlds. He (Allah) said to this man who had striven hard in worship; Had you knowledge about Me or had you power over that which I had in My hand? He said to the man who sinned: Go and enter Paradise by My mercy. He said about the other: Take him to Hell. AbuHurayrah said: By Him in Whose hand my soul is, he spoke a word by which this world and the next world of his were destroyed.  

سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ كَانَ رَجُلاَنِ فِي بَنِي إِسْرَائِيلَ مُتَآخِيَيْنِ فَكَانَ أَحَدُهُمَا يُذْنِبُ وَالآخَرُ مُجْتَهِدٌ فِي الْعِبَادَةِ فَكَانَ لاَ يَزَالُ الْمُجْتَهِدُ يَرَى الآخَرَ عَلَى الذَّنْبِ فَيَقُولُ أَقْصِرْ فَوَجَدَهُ يَوْمًا عَلَى ذَنْبٍ فَقَالَ لَهُ أَقْصِرْ فَقَالَ خَلِّنِي وَرَبِّي أَبُعِثْتَ عَلَىَّ رَقِيبًا فَقَالَ وَاللَّهِ لاَ يَغْفِرُ اللَّهُ لَكَ أَوْ لاَ يُدْخِلُكَ اللَّهُ الْجَنَّةَ فَقُبِضَ أَرْوَاحُهُمَا فَاجْتَمَعَا عِنْدَ رَبِّ الْعَالَمِينَ فَقَالَ لِهَذَا الْمُجْتَهِدِ أَكُنْتَ بِي عَالِمًا أَوْ كُنْتَ عَلَى مَا فِي يَدِي قَادِرًا وَقَالَ لِلْمُذْنِبِ اذْهَبْ فَادْخُلِ الْجَنَّةَ بِرَحْمَتِي وَقَالَ لِلآخَرِ اذْهَبُوا بِهِ إِلَى النَّارِ قَالَ أَبُو هُرَيْرَةَ وَالَّذِي نَفْسِي بِيَدِهِ لَتَكَلَّمَ بِكَلِمَةٍ أَوْبَقَتْ دُنْيَاهُ وَآخِرَتَهُ  

The Prophet ﷺ said: There is no sin more fitted to have punishment meted out by Allah to its perpetrator in advance in this world along with what He stores up for him in the next world than oppression and severing ties of relationship.  

قَالَ رَسُولُ اللَّهِ ﷺ مَا مِنْ ذَنْبٍ أَجْدَرُ أَنْ يُعَجِّلَ اللَّهُ تَعَالَى لِصَاحِبِهِ الْعُقُوبَةَ فِي الدُّنْيَا مَعَ مَا يَدَّخِرُ لَهُ فِي الآخِرَةِ مِثْلُ الْبَغْىِ وَقَطِيعَةِ الرَّحِمِ