John 13:14 Meaning

12So after he had washed their feet, and had taken his garments, and was set down again, he said unto them, Know ye what I have done to you?

13Ye call me Master and Lord: and ye say well; for so I am.

14If I then, your Lord and Master, have washed your feet; ye also ought to wash one another's feet.

15For I have given you an example, that ye should do as I have done to you.

16Verily, verily, I say unto you, The servant is not greater than his lord; neither he that is sent greater than he that sent him.