Narrated 'Abdullah bin 'Amr: A person asked Allah's Apostle . "What (sort of) deeds in or (what qualities of) Islam are good?" He replied, "To feed (the poor) and greet those whom you know and those whom you don't know."
Hadith ReferenceSahih Bukhari / The Book of Belief (Faith) / Hadith: 28
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة