Jesus is doing something rather dramatic in this passage

Look at the verbs! He busies himself with the menial task of a slave
- Jesus is teaching his disciple through a living parable
• he’s not telling a story this time – not explaining a truth
• he is acting out a lesson
- in the Synoptic gospels, Jesus explains the difference of how hierarchy is ordered in his kingdom
You know that those who are considered rulers of the Gentiles lord it over them, and their great ones exercise authority over them. But it shall not be so among you. But whoever would be great among you must be your servant, and whoever would be first among you must be slave of all. For even the Son of Man came not to be served but to serve, and to give his life as a ransom for many (Mk. 10:44-45)
• so here, Jesus shows them what that means
◦ you can be sure, Peter wasn’t only disciple that felt the impact of this lesson
• they would never forget the night Jesus washed their feet