Abu Hurairah (RAA) narrated that the Messenger of Allah (ﷺ) said:

“The young should salute the old, the one who is passing by should salute the one who is sitting, and the small group of people should salute the larger one.” Agreed upon.

وَعَنْ أَبِي هُرَيْرَةَ ‏- رضى الله عنه ‏- قَالَ: [قَالَ] رَسُولُ اَللَّهِ ‏- صلى الله عليه وسلم ‏-{ لِيُسَلِّمْ اَلصَّغِيرُ عَلَى اَلْكَبِيرِ, وَالْمَارُّ عَلَى اَلْقَاعِدِ, وَالْقَلِيلُ عَلَى اَلْكَثِيرِ } مُتَّفَقٌ عَلَيْهِ.‏ [1]‏ .‏