Note 7 at Joh 13:10: There was much more to Jesus washing His disciples' feet than merely their physical cleansing. He was giving them an example of humility that they were supposed to follow (see note 9 at Joh 13:15), but this was also illustrating a spiritual lesson on cleansing from sin.

Two different Greek words are used for "wash" and "washed" in this verse. The word used for "wash" in Joh 13:5-6, 8, and this verse is "NIPTO," and it is the Greek word used in the New Testament to denote "washing part of the body" (Vine's Expository Dictionary) such as the hands or feet (e.g., Mt 15:2 and Mr 7:3). A different Greek word, "LOUO," was translated "washed" in this verse, and it signifies "to bathe, to wash the body" (Vine's Expository Dictionary).

Jesus was saying that just as those who have just bathed don't need another bath when only their feet have gotten dusty, so believers who have received eternal redemption (Heb 9:12) only need an external cleansing from the contact they have had with the world.

Peter's desire to be cleansed from head to toe was commendable but misdirected. In the symbolism that Jesus was using, anyone who has confessed Jesus as Lord (Mt 16:16 and Ro 10:9) has already been cleansed of sin once and for all (Heb 10:10-14 and 12:23). Our spirits have been sanctified and perfected forever, but our bodies and souls can be defiled by sin and need to be cleansed throughout our earthly lives. This is done by confessing and turning from that sin (1Jo 1:9).

Note 8 at Joh 13:10: As explained in Joh 13:11, this was a reference to Judas, the betrayer. The ministry of Jesus to His disciples had cleansed them, and they were completely clean. However, Judas was not cleansed, because of his rejection of Jesus.