Sahih al-Bukhari 12
Sahih Book of Belief · Hadith 12 of 7,563حَدَّثَنَا عَمْرُو بْنُ خَالِدٍ، قَالَ حَدَّثَنَا اللَّيْثُ، عَنْ يَزِيدَ، عَنْ أَبِي الْخَيْرِ، عَنْ عَبْدِ اللَّهِ بْنِ عَمْرٍو ـ رضى الله عنهما ـ أَنَّ رَجُلاً، سَأَلَ النَّبِيَّ صلى الله عليه وسلم أَىُّ الإِسْلاَمِ خَيْرٌ قَالَ " تُطْعِمُ الطَّعَامَ، وَتَقْرَأُ السَّلاَمَ عَلَى مَنْ عَرَفْتَ وَمَنْ لَمْ تَعْرِفْ ".
Narrated by Abdullah bin 'Amr
A man asked the Prophet (ﷺ) , "What sort of deeds or (what qualities of) Islam are good?" The Prophet (ﷺ) replied, 'To feed (the poor) and greet those whom you know and those whom you do not Know (See Hadith No)
References
Sahih al-Bukhari 12
In-book: Book 2, Hadith 5 Source: hadith-api (fawazahmed0)