Origen — as excerpted in the Catena Aurea on John 13:12-20

“(t. xxxii. 7.) Or thus: This spiritual washing of the feet is done primarily by Jesus Himself, secondarily by His disciples, in that He said to them, Ye ought to wash one another’s feet. Jesus washed the feet of His disciples as their Master, of His servants as their Lord. But the object of the master is to make His disciples as Himself; and our Saviour beyond all other masters and lords, wished His disciples to be as their Master and Lord, not having the spirit of bondage, but the spirit of adoption, whereby they cry, Abba, Father. (Rom. 8:19) So then before they become masters and lords, they need the washing of the feet, being as yet insufficient disciples, and savouring of the spirit of bondage. But when they have attained to the state of master and lord, they then are able to imitate their Master, and to wash the disciples’ feet by their doctrine.”