10 Jesus said to him, “He who is bathed needs only to wash his feet, but is completely clean; and you are clean, but not all of you.” 11 For He knew who would betray Him; therefore He said, “You are not all clean.”
Jesus had just mentioned that His true disciples were “clean.” Now He says that there is one exception—Judas. There was a traitor in their midst. 13:10c
but not [emphatic] all of you.”
Jesus had just made the statement that His disciples were “clean,” but with this phrase He had to qualify that statement. Judas was no believer; he had not taken the bath of cleansing from Christ. Jesus had washed his feet, but he had not taken a bath. No rite can cleanse someone, even if performed by Jesus Himself.
This phrase refers to Judas, a close but unsavory colleague of Jesus. Thus, it is clear that Jesus did not refer to physical cleansing when referring to Peter but to spiritual, the need for spiritual birth.
For He knew who would betray Him;
It was no surprise to Jesus that Judas would betray Him. He knew it all along (Jn 2:25; 4:29).
therefore He said, “You are not all clean.”
A disciple of Jesus who walked with Him for three years had never believed on Him. Footwashing would make no difference to Judas. He could not serve because he was never a believer in the first place.
No amount of grace exercised on some people has any effect.
The condescension of Christ was to wash the feet of the disciples, including Judas. This act of humility made no impression on His betrayer. Judas’ intransigence was implacable. His heart was hard as iron. As Scripture says, “The dog will return to his vomit.” No amount of grace exercised toward some people has an effect on them.