Riyad as-SalihinChapter 17Hadith 916
Full Sharh — Riyad as-Salihin 916
وعن أبي هريرة رضي الله عنه قال: قال رسول الله صلى الله عليه وسلم : "لا يحل لمسلم أن يهجر أخاه فوق ثلاث، فمن هجر فوق ثلاث، فمات دخل النار".((رواه أبو داود بإسناد على شرط البخاري)).
English Translation
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.".
Source
Riyad as-Salihin(رياض الصالحين)
The Book of the Prohibited actions
Hadith Number
916