The Messenger of Allah ﷺ said: It is not right for a Muslim to keep apart from another Muslim for more than three days. Then when he meets him and gives three salutations, receiving during that time no response, the other bears his sin.
أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ لاَ يَكُونُ لِمُسْلِمٍ أَنْ يَهْجُرَ مُسْلِمًا فَوْقَ ثَلاَثَةٍ فَإِذَا لَقِيَهُ سَلَّمَ عَلَيْهِ ثَلاَثَ مِرَارٍ كُلُّ ذَلِكَ لاَ يَرُدُّ عَلَيْهِ فَقَدْ بَاءَ بِإِثْمِهِ