Now before the Feast of the Passover, when Jesus knew that his hour had come to depart out of this world to the Father, having loved his own who were in the world, he loved them to the end. During supper, when the devil had already put it into the heart of Judas Iscariot, Simons son, to betray him, Jesus, knowing that the Father had given all things into his hands, and that he had come from God and was going back to God, rose from supper. He laid aside his outer garments, and taking a towel, tied it around his waist. Then he poured water into a basin and began to wash the disciples feet and to wipe them with the towel that was wrapped around him. He came to Simon Peter, who said to him, Lord, do you wash my feet? Jesus answered him, What I am doing you do not understand now, but afterward you will understand. Peter said to him, You shall never wash my feet. Jesus answered him, If I do not wash you, you have no share with me. Simon Peter said to him, Lord, not my feet only but also my hands and my head! Jesus said to him, The one who has bathed does not need to wash, except for his feet, but is completely clean. And you are clean, but not every one of you. For he knew who was to betray him; that was why he said, Not all of you are clean.
When he had washed their feet and put on his outer garments and resumed his place, he said to them, Do you understand what I have done to you? You call me Teacher and Lord, and you are right, for so I am. If I then, your Lord and Teacher, have washed your feet, you also ought to wash one anothers feet. For I have given you an example, that you also should do just as I have done to you. Truly, truly, I say to you, a servant is not greater than his master, nor is a messenger greater than the one who sent him. If you know these things, blessed are you if you do them. . . .
Now is the Son of Man glorified, and God is glorified in him. If God is glorified in him, God will also glorify him in himself, and glorify him at once. Little children, yet a little while I am with you. You will seek me, and just as I said to the Jews, so now I also say to you, Where I am going you cannot come. A new commandment I give to you, that you love one another: just as I have loved you, you also are to love one another. By this all people will know that you are my disciples, if you have love for one another.
And Pastor, the part the blood of Jesus has washed clean is the spirit, where according to 1John3:9 God then abides so that the clean part cannot get dirty again, while the Holy Spirit works on the soul (behavior mechanism), to gain our cooperation in His cleaning up that, too.