We unlearn bad behaviors by repeating and practicing good behaviors. That is built into human development. We have erred in making discipleship all about “what we know” instead of “what we do”. The former can be driven by pride; the latter must be driven by humility. Jesus’ disciples wanted chief seats, used a little politics, and a lot of jockeying to get there. This was a behavior that did not fit with a Christ follower. So Jesus gave them an object lesson in a different behavior He wanted to see in them; He washed their feet and instructed them to put that into practice in their lives. There is nothing like practicing serving to break the habit of wanting to be served.
“If I then, your Lord and Teacher, have washed your feet, you also ought to wash one another’s feet. For I have given you an example, that you also should do just as I have done to you.” (John 13:14-15 ESV)
From “Growing Toward Maturity”, by H. Lamar Smith.