John 13:12-15

So when He had washed their feet and put on His [outer] robe and reclined at the table again, He said to them, “Do you understand what I have done for you? You call Me Teacher and Lord, and you are right in doing so, for that is who I am. So if I, the Lord and the Teacher, washed your feet, you ought to wash one another’s feet as well. For I gave you [this as] an example, so that you should do [in turn] as I did to you.