Al-Ṭufayl b. Ubay b. Ka’b narrated that he used to come to ʿAbdullāh b. ʿUmar and go with him to the market. He said, “Whenever we went to the market, ʿAbdullāh b. ʿUmar would never pass a cheap goods merchant, a seller, a poor person or anyone else except that he would greet them with salāms.” He continued, “So I came to him one day and he asked me to go to the market with him. I said, ‘And what are you going to do at the market? You never stop to buy anything, you never ask about goods, you never price anything and you never sit in the market gatherings. Sit with us here and we can talk. So he said to me, ‘O Abū Baṭn (i.e. possessor of the belly; Al-Ṭufayl had a big belly)! We only go out for salāms, to greet those we meet.’’”
Al-Bukhārī, Al-Adab Al-Mufrad, Al-Albānī’s Ṣaḥīḥ Al-Adab Al-Mufrad Vol. 1 p395.