by Imam Muslim, translation by Abdul Hamid Siddiqui , Volume: The Book of Faith (Kitab Al-Iman)
Chapter: CONCERNING THE EMINENCE OF ISLAM AND OF THE AFFAIRS WHICH ARE EXCELLENT
It is narrated on the authority of 'Abdullah b. 'Amr that a man asked the Messenger of Allah (may peace and blessings be upon him) which of the merits (is superior) in Islam. He (the Holy Prophet) remarked: That you provide food and extend greetings to one whom you know or do not know.
'Abdullah b. Amr b. al-As is reported to have said: Verily a person asked the Messenger of Allah (may peace and blessings be upon him) who amongst the Muslims was better. Upon this (the Holy Prophet) remarked: From whose hand and tongue the Muslims are safe.
It is narrated on the authority of Jabir that he heard the (Holy Prophet) say: A Muslim is he from whose hand and tongue the Muslim's are safe.
It is narrated on the authority of Abu Musa Ash'ari: I asked the Messenger of Allah which (attribute) of Islam is more excellent. Upon this he remarked: One in which the Muslims are safe, protected from the tongue and hand of (other Muslims). Ibrahim b. Sa'id al-Jauhari has narrated this hadith with the same words in addition to these. The Messenger of Allah (may peace and blessings be upon him) was asked as to who amongst the Muslims is better, and the rest of the hadith was narrated like this.