كتاب البر والصلة والآداب
45  
The Book of Virtue, Enjoining Good Manners, and Joining of the Ties of Kinship
(8)
Chapter: The Prohibition Of Forsaking Someone For More Than Three Days For No Legitimate Reason
(8)
باب تَحْرِيمِ الْهَجْرِ فَوْقَ ثَلاَثٍ بِلاَ عُذْرٍ شَرْعِيٍّ ‏‏
Sahih Muslim 2560 a

Abu Ayyub Ansiri reported Allah's Messenger (ﷺ) as saying:

It is not permissible for a Muslim to have estranged relations with his brother beyond three nights, the one turning one way and the other turning the other way when they meet; the better of the two is one who is the first to give a greeting.
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنِ ابْنِ شِهَابٍ، عَنْ عَطَاءِ بْنِ يَزِيدَ، اللَّيْثِيِّ عَنْ أَبِي أَيُّوبَ الأَنْصَارِيِّ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏ "‏ لاَ يَحِلُّ لِمُسْلِمٍ أَنْ يَهْجُرَ أَخَاهُ فَوْقَ ثَلاَثِ لَيَالٍ يَلْتَقِيَانِ فَيُعْرِضُ هَذَا وَيُعْرِضُ هَذَا وَخَيْرُهُمَا الَّذِي يَبْدَأُ بِالسَّلاَمِ ‏"‏ ‏.‏
Reference : Sahih Muslim 2560a
In-book reference : Book 45, Hadith 31
USC-MSA web (English) reference : Book 32, Hadith 6210
  (deprecated numbering scheme)