That you provide food and extend greetings to one whom you know or do not know.
Sahih Muslim Book 1, Hadith 67
← Previous Hadith I asked the Messenger of Allah to tell me about Islam a thing which might dispense with the necessity of my asking anybody after you. In the hadith of Abu Usama the (words) are: other than you. He (the Holy Prophet) remarked: Say I affirm my faith in Allah and then remain steadfast to it.

Sahih Muslim Book 1, Hadith 66 Next Hadith → 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.

Sahih Muslim Book 1, Hadith 68