It is narrated from Prophet Jesus/Isa (AS) who told his companions:

I have a request from you, if you promise that you will do it, and then I tell you about it. They said: We accept. Prophet Jesus (AS) washed their feet and they became very surprised. When the task finished, the companions said: This was our duty to wash your feet. Jesus (AS) said: I wanted to make this to be understood that the more deserving person to serve people, is the learned one. I wanted to teach you the lesson of humbleness. Basically wisdom grows in the bed of humbleness and not in the land of arrogance; as the plants grow in soft land, and not in the hard land in the mountains [1].

[1] Dastaan-e-Rastaan, Page 172.

Source: en.shafaqna.com