washed clean

 Jesus answered him, “What I am doing you do not understand now, but afterward you will understand.”
(John 13:7)

Jesus washing the disciples feet was not his greatest act of service, it pointed forward towards the washing/cleansing he was about to perform on the cross. If you are a Christian, Jesus has washed you clean. 

let us draw near with a true heart in full assurance of faith, with our hearts sprinkled clean from an evil conscience and our bodies washed with pure water.
(Hebrews 10:22 ESV)

Husbands, love your wives, as Christ loved the church and gave himself up for her, that he might sanctify her, having cleansed her by the washing of water with the word, so that he might present the church to himself in splendor, without spot or wrinkle or any such thing, that she might be holy and without blemish.
(Ephesians 5:25-27 ESV)
No matter what you have done or what has been done to you, you are clean. The only way we can truly serve others out of love, including our enemies, is by recognising that we serve because we have been served. We love because he first loved us (1 John 4:19)