Hadith 21

Sahih Bukhari

Book 2: Belief

Chapter 20

To greet is a part of Islam

باب إِفْشَاءُ السَّلاَمِ مِنَ الإِسْلاَمِ

And 'Ammar said, "Whoever acquires the following three qualities will acquire faith: 1. To treat others as one likes to be treated by others. 2. To greet everybody (known and unknown). 3. To spend (give charitable gifts) in Allah's Cause, in spite of poverty."
وَقَالَ عَمَّارٌ: ثَلاَثٌ مَنْ جَمَعَهُنَّ فَقَدْ جَمَعَ الإِيمَانَ الإِنْصَافُ مِنْ نَفْسِكَ، وَبَذْلُ السَّلاَمِ لِلْعَالَمِ، وَالإِنْفَاقُ مِنَ الإِقْتَارِ.
Sahih al-Bukhari 28
حَدَّثَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا اللَّيْثُ، عَنْ يَزِيدَ بْنِ أَبِي حَبِيبٍ، عَنْ أَبِي الْخَيْرِ، عَنْ عَبْدِ اللَّهِ بْنِ عَمْرٍو، أَنَّ رَجُلاً، سَأَلَ رَسُولَ اللَّهِ صلى الله عليه وسلم أَىُّ الإِسْلاَمِ خَيْرٌ قَالَ ‏ ‏‏.‏
"‏ تُطْعِمُ الطَّعَامَ، وَتَقْرَأُ السَّلاَمَ عَلَى مَنْ عَرَفْتَ وَمَنْ لَمْ تَعْرِفْ ‏"
'Abdullah bin 'Amr:

A person asked Allah's Messenger (ﷺ) . "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."