Hubaish bin Juz Sulami reported,

Muawiya wrote to Abdul-Rahman bin Shibl, instructing him to teach the people what he had heard from the Messenger of Allah ﷺ. So he gathered them together and said, "I heard the Messenger of Allah ﷺ say, 'The rider greets the one on foot, the one on foot greets the one sitting, and the smaller group greets the larger. Whoever answers the greeting, it counts in his favor, and whoever does not answer gains nothing from it.'"

ثم قال يسلم الراكب على الراجل والراجل على الجالس والأقل على الأكثر فمن أجاب السلام كان له ومن لم يجب فلا شيء له