Anas (May Allah be pleased with him) reported that he passed by some children and greeted them. Then he said:
"Messenger of Allah (ﷺ) used to do the same."[Al-Bukhari and Muslim]. (ES)
App reference (ES): Book 6, Hadith 18 (ES)
Arabic/English book reference (ES): Book 6, Hadith 862 (ES)