Bismillahirrahmanirrahim
Mafhum-e-Hadith: Bachchon ko bhisalam kiya karo
Anas Bin malik Radhi Allahu Anhu se rivayat hai ki jab wo bachhcon ke pass se guzre to unhone bachchon ko salam kiya aur kaha ki Rasool-Allah Sal-Allahu Alaihi Wasallam bhi aisa hi kiya karte the (yani bachchon ko salam karte they)
Sahih Bukhari, Vol 7, 6247
Narrated Anas bin Malik Radhi Allahu Anhu : that he passed by a group of boys and greeted them and said, “The Prophet Sal-Allahu Alaihi Wasallam used to do so.”
Sahih Bukhari, Vol 8, Book 74, No. 264: