John 13:10 (NKJV)
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."
Jesus was answering Peter, an all or nothing kind of guy, who at first recoiled from having his feet washed by Jesus but then, decided that if it meant having fellowship with Jesus he wanted the whole bath. The bath represents being saved and made righteous by God when first becoming a believer. Jesus says that for his disciples, there is no need to be bathed again since that has already been done. It is true that we are cleansed from our sin when we are saved by God's forgiveness, but what about when we sin again after being saved? Jesus answers this wonderfully here in this verse. No need to be saved again, that is already done, just wash up those small parts that are dirty. How is that done? By confessing or agreeing with God on a continual basis.
1 John 1:9 (NKJV)
If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness.
In this way, we can keep a short account with God and stay close and clean.