Abu Ayyub Al-Ansari (May Allah be pleased with him) said:
The Messenger of Allah (ﷺ) said, "It is not lawful for a Muslim to desert (stop talking to) his brother beyond three nights, the one turning one way and the other turning to the other way when they meet, the better of the two is one who is the first to greet the other."[Al-Bukhari and Muslim].
App reference: Book 18, Hadith 82
Arabic/English book reference: Book 18, Hadith 1592