Abu Hurairah (May Allah be pleased with him) said:
The Messenger of Allah (ﷺ) said, "It is not lawful for a Muslim to forsake his (Muslim) brother beyond three days; and whosoever does so for more than three days, and then dies, will certainly enter the Hell."[Abu Dawud].
App reference: Book 18, Hadith 85
Arabic/English book reference: Book 18, Hadith 1595