(55) باب فِيمَنْ يَهْجُرُ أَخَاهُ الْمُسْلِمَ
Abu Ayyub al-Ansari reported the Messenger of Allah (May peace be upon him) as saying :
it is not allowable for a Muslim to keep apart from his brother for more than three days. When they meet, this turns away from him, and that turns away from him. The better of the two is the one who initiates in salutation.
Reference: Sunan Abi Dawud 4911
In-book reference: Book 43, Hadith 139
English translation: Book 42, Hadith 4893