Abu Ayyub Al-Ansari (May Allah be pleased with him) said:
The Messenger of Allah (Sallallahu Alaihi Wasallam) 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].