A man asked the Messenger of Allah (May peace be upon him): When aspect of Islam is best? He replied: that you should provide food and greet both those you know and those you do not know. (Using translation from Abū Dāʾūd 5194)
أَنَّ رَجُلًا سَأَلَ النَّبِيَّ ﷺ أَيُّ الْأَعْمَالِ خَيْرٌ؟ قَالَ أَنْ تُطْعِمَ الطَّعَامَ وَتَقْرَأَ السَّلَامَ عَلَى مَنْ عَرَفْتَ وَمَنْلَمْ تَعْرِفْ