Our own pride discourages Him from washing our feet. Once our pride is gone, He can do His best work.

John 13:1-15

It was before the festival of the Passover, and Jesus knew that the hour had come for him to pass from this world to the Father. He had always loved those who were his in the world, but now he showed how perfect his love was.
They were at supper, and the devil had already put it into the mind of Judas Iscariot son of Simon, to betray him. Jesus knew that the Father had put everything into his hands, and that he had come from God and was returning to God, and he got up from table, removed his outer garment and, taking a towel, wrapped it round his waist; he then poured water into a basin and began to wash the disciples’ feet and to wipe them with the towel he was wearing. He came to Simon Peter, who said to him, ‘Lord, are you going to wash my feet?’ Jesus answered, ‘At the moment you do not know what I am doing, but later you will understand.’ ‘Never!’ said Peter ‘You shall never wash my feet.’ Jesus replied, ‘If I do not wash you, you can have nothing in common with me.’ ‘Then, Lord,’ said Simon Peter ‘not only my feet, but my hands and my head as well!’ Jesus said, ‘No one who has taken a bath needs washing, he is clean all over. You too are clean, though not all of you are.’ He knew who was going to betray him, that was why he said, ‘though not all of you are.’
When he had washed their feet and put on his clothes again he went back to the table. ‘Do you understand’ he said ‘what I have done to you? You call me Master and Lord, and rightly; so I am. If I, then, the Lord and Master, have washed your feet, you should wash each other’s feet. I have given you an example so that you may copy what I have done to you.’