Sahih Muslim 2561
Sahih Muslim · Book 45: The Book of Virtue, Enjoining Good Manners, and Joining of the Ties of Kinship · The Prohibition Of Forsaking Someone For More Than Three Days For No Legitimate Reason
'Abdullah b. 'Umar reported Allah's Messenger (ﷺ) as saying:
حَدَّثَنَا مُحَمَّدُ بْنُ رَافِعٍ ، حَدَّثَنَا مُحَمَّدُ بْنُ أَبِي فُدَيْكٍ ، أَخْبَرَنَا الضَّحَّاكُ، - وَهُوَ ابْنُ عُثْمَانَ - عَنْ نَافِعٍ ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " لاَ يَحِلُّ لِلْمُؤْمِنِ أَنْ يَهْجُرَ أَخَاهُ فَوْقَ ثَلاَثَةِ أَيَّامٍ " .
It is not permissible for a Muslim to have estranged relations with his brother beyond three days.