Narrated 'Abdullah bin 'Amr: A man asked the Prophet, "What Islamic traits are the best?" The Prophet said, "Feed the people, and greet those whom you know and those whom you do not know."
Hadith Referenceصحيح البخاري / كتاب الاستئذان / 6236
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة
Narrated Abu Aiyub: The Prophet said, "It is not lawful for a Muslim to desert (not to speak to) his brother Muslim for more than three days while meeting, one turns his face to one side and the other turns his face to the other side. Lo! The better of the two is the one who starts greeting the other."
Hadith Referenceصحيح البخاري / كتاب الاستئذان / 6237
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة