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]. (DE)
App reference (DE): Book 6, Hadith 18 (DE)
Arabic/English book reference (DE): Book 6, Hadith 862 (DE)