Messenger of Allah ﷺ said, "The riding one should greet the walking one, and the walking one should greet the sitting one, and the small number of persons should greet the large number of persons."  

قَالَ رَسُولُ اللَّهِ ﷺ يُسَلِّمُ الرَّاكِبُ عَلَى الْمَاشِي وَالْمَاشِي عَلَى الْقَاعِدِ وَالْقَلِيلُ عَلَى الْكَثِيرِ