Messenger of Allah ﷺ said, "The riding person 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."  

عَنْ رَسُولِ اللَّهِ ﷺ أَنَّهُ قَالَ يُسَلِّمُ الرَّاكِبُ عَلَى الْمَاشِي وَالْمَاشِي عَلَى الْقَاعِدِ وَالْقَلِيلُ عَلَى الْكَثِيرِ