Sunan Abi Dawud, Hadith 4916

Abu Hurairah reported the Messenger of Allah (May peace be upon him) as saying: The gates of Paradise are opened on Mondays and Thursdays, and forgiveness is granted to every man who does not associate anything with Allah, except for a man between whom and his brother there is rancor. Command will be given that they should be given respite till they conciliate. Abu Dawud said: The Prophet kept apart from some of his wives for forty days, and Ibn 'Umar kept apart from his son till he died. Abu Dawud said: If keeping apart is meant for the sake of Allah, then it has no concern with it. 'Umar bin 'Abd al-'Aziz covered his face from a man.

حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا أَبُو عَوَانَةَ، عَنْ سُهَيْلِ بْنِ أَبِي صَالِحٍ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏ "‏ تُفْتَحُ أَبْوَابُ الْجَنَّةِ كُلَّ يَوْمِ اثْنَيْنِ وَخَمِيسٍ فَيُغْفَرُ فِي ذَلِكَ الْيَوْمَيْنِ لِكُلِّ عَبْدٍ لاَ يُشْرِكُ بِاللَّهِ شَيْئًا إِلاَّ مَنْ بَيْنَهُ وَبَيْنَ أَخِيهِ شَحْنَاءُ فَيُقَالُ أَنْظِرُوا هَذَيْنِ حَتَّى يَصْطَلِحَا ‏" ‏ ‏.‏ قَالَ أَبُو دَاوُدَ النَّبِيُّ صلى الله عليه وسلم هَجَرَ بَعْضَ نِسَائِهِ أَرْبَعِينَ يَوْمًا وَابْنُ عُمَرَ هَجَرَ ابْنًا لَهُ إِلَى أَنْ مَاتَ ‏.‏ قَالَ أَبُو دَاوُدَ إِذَا كَانَتِ الْهِجْرَةُ لِلَّهِ فَلَيْسَ مِنْ هَذَا بِشَىْءٍ وَإِنَّ عُمَرَ بْنَ عَبْدِ الْعَزِيزِ غَطَّى وَجْهَهُ عَنْ رَجُلٍ ‏.‏

sunnah.com

also referenced under: Hadith 4898 (Hasan)