Hazrat Khalifatul-Masih V (may Allah be his Helper) stated:
“One can gauge from the following narration how the Holy Prophet (peace and blessings of Allah be upon him) would draw attention to promoting the greeting of Salam, to its blessings, and to the establishment of gatherings filled with peace and prayers.
“Hazrat Abu Hurairah (may Allah be pleased with him) relates that the Holy Prophet (peace and blessings of Allah be upon him) was sitting in a gathering when a man passed by and said, Assalamu Alaikum. The Holy Prophet (peace and blessings of Allah be upon him) said: ‘Ten good deeds.’ Then another person passed by and said, Assalamu Alaikum wa Rahmatullah, and he said: ‘Twenty good deeds.’ Then another passed by and said, Assalamu Alaikum wa Rahmatullahi wa Barakatuhu, and he said: ‘Thirty good deeds.’
“Then a man rose from the gathering and did not offer Salam. The Messenger of Allah (peace and blessings of Allah be upon him) said: ‘It seems that your companion has forgotten. When any of you comes to a gathering, he should greet with Salam. If he finds space, he should sit down, and when he rises to leave, he should again offer Salam.’ [Al-Adab al-Mufrad, Hadith 1015]
“One should also greet with Salam when coming and going.
“In another narration, Hazrat Bara (may Allah be pleased with him) relates that the Messenger of Allah (peace and blessings of Allah be upon him) said: ‘Spread Salam. By doing so, you will live in peace; your homes and your society will also come to enjoy peace.’ [At-Targhib wat-Tarhib, Hadith 3979]
“In yet another narration, Hazrat Abu Darda (may Allah be pleased with him) relates that the Messenger of Allah (peace and blessings of Allah be upon him) said: ‘Spread Salam so that you may attain victory.’ [At-Targhib wat-Tarhib, Hadith 3984]
“Thus, by spreading Salam, bonds of mutual love will be established. These bonds of love will generate a collective strength within the Jama’at, and it is this communal strength and unity that will ultimately create the conditions for victory. Otherwise, if division prevails among you, if peace is absent, and if no effort is made to promote it, then the strength of the Jama’at will be lost.”
[Friday Sermon, May 25, 2007; Khutbat-e-Masroor, vol. 5, pp. 217–218, translated from Urdu]