John 13:13

For he knew him who would betray him, therefore he said, "You are not all clean."

So when he had washed their feet, put his outer garment back on, and sat down again, he said to them...

If I then, the Lord and the Teacher, have washed your feet, you also ought to wash one another's fee...

For I have given you an example, that you also should do as I have done to you.