(189) بَابُ هِجْرَةِ الْمُسْلِمِ
Anas ibn Malik reported that the Messenger of Allah, may Allahbless him and grant him peace, said, "Do not hate one another nor envyone another nor shun one another. Slaves of Allah, be brothers! It is notlawful for a Muslim to refuse to speak to his brother (Muslim) for morethan three nights."
Reference: Al-Adab Al-Mufrad 398
In-book reference: Book 22, Hadith 2
English translation: Book 22, Hadith 398