Hawzah News Agency – The merciful prophet of Islam (pbuh) says:

لا تَدابَرُوا، ولا تَقاطَعُوا، وكُونوا عِبادَ اللَّهِ إخواناً، هَجرُ المُؤمنَينِ ثَلاثاً، فإن تَكَلَّما وإلّا أعرَضَ اللَّهُ عَزَّوجلَّ عَنهُما حتّى‏ يَتَكلَّما.

'Do not turn your backs to each other and do not cut ties amongst yourselves, and be servants of Allah as brothers. Deserting a believer for [more than] three days [is not allowed] and they must speak [thereafter], but if they do not Allah Almighty turns away from them until they speak.'

Source: al-Targhib wa al-Tarhib, v. 3, p. 457, no. 8