Note 7 at Jn. 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 Jn. 13:15, p. 418) but this was also illustrating a spiritual lesson on cleansing from sin.

There are two different Greek words used for "wash" and "washed" in this verse. The word used for "wash" in verses 5- 6,8, and this verse is "nipto" which is the Greek word used in the New Testament to denote washing part of the body such as the hands or feet (e.g. Mt. 15:2; Mk. 7:3). A different Greek word "louo" was translated "washed" in this verse and it signifies "to bathe; to wash the body" (W.E. Vine).

Jesus is saying that just as a person who has just bathed doesn't need another bath when only his feet have gotten dusty, so a believer who has received eternal redemption (Heb. 9:12) only needs an external cleansing from the contact he has 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; Rom. 10:9) has already been cleansed of sin once and for all (Heb. 10:10-14; 12:23). Our spirit has been sanctified and perfected forever but our body and soul can be defiled by sin and need to be cleansed throughout our earthly lives by confessing and turning from that sin (1 Jn. 1:9).

Note 8 at Jn. 13:10: As explained in the next verse, 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.