At-Tufail bin Ubayy bin Ka'b (May Allah be pleased with him) reported:
I used to visit 'Abdullah bin 'Umar (May Allah be pleased with them) in the morning and accompany him to the market. 'Abdullah offered greetings of peace to every one he met on the way, be they sellers of petty goods, traders or poor people. One day when I came to him, he asked me to accompany him to the market. I said to him: "What is the point of your going to the market when you do not sell, nor ask about articles, nor offer a price for them, nor sit down with any company of people. Let us sit down here and talk." He replied: "O Abu Batn (belly)! (Tufail had a large belly), we go to the market to greet everyone we meet."[Malik].
App reference: Book 6, Hadith 6
Arabic/English book reference: Book 6, Hadith 850