حَدَّثَنَا أَحْمَدُ بْنُ حَنْبَلٍ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ، أَخْبَرَنَا مَعْمَرٌ، عَنْ هَمَّامِ بْنِ مُنَبِّهٍ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ يُسَلِّمُ الصَّغِيرُ عَلَى الْكَبِيرِ وَالْمَارُّ عَلَى الْقَاعِدِ وَالْقَلِيلُ عَلَى الْكَثِيرِ ‏"‏ ‏.‏

Abu Hurairah reported the Messenger of Allah (May peace be upon him) as saying : The young should salute the old, the one who is passing by should salute the one who is sitting, and a small company should salute a large one. Translation Not Available

Book Ref: Sunan Abi Dawud Book 43 Hadith 5198
Web Ref:  Sunan Abi Dawud Book 42 Hadith 5179