One of the signs of the Last Hour is to restrict one's use of the Islamic greetings to those who are known to one. If a Muslim meets another brother, unknown to him, and he does not greet him, he is violating the Sunnah of the Prophet, sallallahu `alaihi wa sallam. The Prophet's teaching is to greet a Muslim regardless of whether we know that Muslim. These greetings enhance the harmony and peace between Muslims.
It is narrated on the authority of `Abdullah ibn Mas`ood: The Messenger of Allah, sallallahu `alaihi wa sallam, said, what means: "Verily, in the presence of the Last Hour, giving salam would be limited to those known, trade would spread, until even a wife assigns her husband to trade for her, ties of kinship would be broken, and false testimony, concealing evidence and the calligraphic style (reed pen) would appear." (A sound hadith related by Ahmad and Hakim).
`Abdullah ibn Mas`ood reported: The Messenger of Allah, sallallahu `alaihi wa sallam, said: Verily, among the signs of the Hour is that greeting (of Islam) is limited to those known only. In another report: A man will greet 'salaam' only to his intimate fellow. (A sound hadith narrated by Ahmad)
