I'm currently studying John 13:1-20. I go to a church where they believe that foot washing is an ordinance similar to baptism and the Lord's supper. I personally disagree and believe that as Jesus said, v.15 (ESV)
For I have given you an example, that you also should do just as I have done to you.
I believe that Jesus is demonstrating that if the greatest (being Jesus) is willing to serve the lowliest of tasks, we too should be willing to serve one another in humility. So I understand that as acts of kindness and service (which can obviously take many forms).
Where I'm really struggling from an exegetical perspective is in v10 which says
Jesus said to him, “The one who has bathed does not need to wash, except for his feet, but is completely clean.
My assumption is that Jesus meant by you are already completely clean, is that by faith in Christ they have been cleansed of all sin, and have transferred from the kingdom of darkness to the kingdom of light.
So my question finally is, what connection does the symbol of washing only the feet have to do with the cleansing of the overall body. If the cleansing of the body is the forgiveness of sin by grace through faith, then what does the washing of the feet symbolically represent, and how does that link back to forgiveness of sin? I hope that makes sense. If you need any clarifications please let me know.