From Sahih Bukhari (Hadith 2888):
Narrated Anas:I was in the company of Jabir bin `Abdullah on a journey and he used to serve me though he was older than I. Jarir said, "I saw the Ansar doing a thing (i.e. showing great reverence to the Prophet (ﷺ) ) for which I have vowed that whenever I meet any of them, I will serve him
Reference: Bukhari 2888