The most obvious reference to me is that they are free of mortal sin, washed, but still have some attachment to sin or venial sin that remains. So it can be forgiven and our feet “washed” by the Lord’s Supper/Eucharist that is soon to happen. It is also forgiven in the prayers of repentance at the beginning of Mass, and the prayers the priest prays just before the Eucharistic Prayer along with the ceremonial washing. The eleven Apostles are holy, even though they are not fully purged of all venial sin and attachment to sin.
The “not all” refers to Judas, who retains mortal sin and is not “washed”.
I’m certain there are probably many more understandings to the verse as well.
I like the story of the washing of the feet. Much can be gleaned from this story. I think my favorite though is the one of The Prodigal Son. Priests like this one a lot too. At least the ones I know.
Okay. We do seem to concentrate a lot on sin. I’ll put forward a little bit of what I get from it.
The washing of the feel in John 13 is often referred to as showing how Jesus is teaching the disciples that they are to be of service to one another, and the “world” and Jesus was showing them that He was in service to them. They are to wash feet as He was washing their feet.
Another aspect of this story is that we must accept the love of God. Is this an easy thing to do? Jesus was washing the feet of the apostles. He was showing them how they were to love one another in action., as He clearly stated in verse 35. “By this shall all men know that you are my disciples, that you love one another.”
So Peter says to the Lord: “Never shall you wash my feet!” (verse 8) And Jesus answered him, “If I do not wash you, you have no part with me.” (verse 8). Love is not easy to accept sometimes. Have you ever had to have your feet washed? it could be embarrasing, it means you can’t do it yourself, it means you have to depend on others, it means you have to lower yourself - and love the person who is doing the washing for you.
And in verses 9 and 10 Peter asks for his head and hands to be washed too, besides his feet, to which Jesus answers. “He who has bathed needs only to wash his feet, but is completely clean, and you ARE clean (but not all of you).”
The not all of you refers to Judas, as you said, so let’s put that aside.
The passage has a big historical sense to it too. People prepared for the Passover. I’m sure the apostles prepared for it as well. They literally washed their whole body, but, as was the custom, feet got dirty when walking because of the dust on the streets and it was customary for there to be some type of feet washing when one got to the others’s home.
Spiritually speaking, the apostles were probably all baptized with John’s baptism. Which was a baptism of repentence and meant that the person had repented and converted and wanted to walk with God. So they were all clean in that sense. They were justified in the eyes of God. But their feet got dirty. So, although we are justified, we still will sin and that always needs to be washed away. This is what you stated above.
Always looking for different spiritual interpretations!
Fran