Abu Huraira reported: The Messenger of Allah, peace and blessings be upon him, said:


تُفْتَحُ أَبْوَابُ الْجَنَّةِ يَوْمَ الِاثْنَيْنِ وَيَوْمَ الْخَمِيسِ فَيُغْفَرُ لِكُلِّ عَبْدٍ لَا يُشْرِكُ بِاللَّهِ شَيْئًا إِلَّا رَجُلًا كَانَتْ بَيْنَهُ وَبَيْنَ أَخِيهِ شَحْنَاءُ فَيُقَالُ أَنْظِرُوا هَذَيْنِ حَتَّى يَصْطَلِحَا أَنْظِرُوا هَذَيْنِ حَتَّى يَصْطَلِحَا أَنْظِرُوا هَذَيْنِ حَتَّى يَصْطَلِحَا


The gates of Paradise are opened on Monday and Thursday. Allah forgives every servant who does not associate anything with him except a man with hatred between himself and his brother. It will be said: Delay these two until they reconcile, delay these two until they reconcile.


Source: Sahih Muslim 2565