“Unless I wash you, you have no part with me.” John 13: 8 please explain.
Jesus answered him, if I wash thee not, thou hast no part with me;
he does not say, if I wash not thy feet, but thee, meaning not with water, but with his blood, and by his Spirit; for Christ uses the word wash here, not literally, but in a mystical and figurative sense, and takes an occasion, as he sometimes does, from things natural, to discourse of things spiritual: moreover, he does not say, thou hast no part “in” me, but thou hast no part “with” me, that is, no fellowship and communion with me; see ( 2 Corinthians 6:14 2 Corinthians 6:15 ) ; and it is as if he should say, Peter, if I had not washed thee with the washing of regeneration by my Spirit, and if I should not shed my blood for thee, and wash thee in it from thy sins, sad would be thy case; thou couldest have no communion with me in this world, nor any part and portion with me in the heavenly inheritance hereafter. Hence it may be observed, that unless a man is washed by Christ, he can have no part with him in this, or the other world. God’s elect have a part, an interest in Christ through eternal, electing, and covenant grace, and in consequence of this are washed by Christ both with his blood, and with the washing of regeneration: and this is done in order that they may have a part with Christ, spiritual fellowship with him now, and possess with him the undefiled inheritance, when time shall be no more.
And, to add to what @Jude has already said:
1 Corinthians 6:11 King James Version (KJV)
11 And such were some of you: but ye are washed, but ye are sanctified, but ye are justified in the name of the Lord Jesus, and by the Spirit of our God.
There is salvation in no one else! God has given no other name under heaven by which we must be saved."
This means that we receive the grace from Jesus Christ to cleanse our sins, or we cannot be saved.
In the last supper, Jesus cleaned feet of his disciples. The meaning of washing one’s feet is to wash one’s sins. Jesus had the dinner with his disciples a few hours before heading to the cross. It was the last supper. We can see humility and love in Jesus who was wearing towels and washing his disciples’ feet. This is the place where they eat a bread and drink a wine with Jesus. Actually Jesus became the bread of life for us. He sacrifices and empties himself to give his life for us. When we live on this bread, our lives can change and be saved.
This is the way of glorigication. After we justification, we need grace to wash our sin. Then we can wash our sin, and we can like Jesus Christ.
This the verse talking about justification. The ones have been washed by the blood of Christ are justified indeed.