Jesus washing the feet of the disciples (John 13:1–17) occurred in the upper room, just prior to the Last Supper.
"If I then, the Lord and the Teacher, washed your feet, you also ought to wash one another's feet. For I gave you an example that you also should do as I did to you. Truly, truly, I say to you, a slave is not greater than his master, nor is one who is sent greater than the one who sent him. If you know these things, you are blessed if you do them." John 13:14-17 NASB https://bible.com/bible/100/jhn.13.14-17.NASB
In verse 14, Jesus says, "For I gave you an example that you also should do as I did to you."
It seems that most Christians today interpret this command symbolically as a though Jesus would have us to serve the body of believers as he did.
What principal of hermeneutics helps us know how to interpret Jesus' statement as a literal command or a symbolic command? How do you apply this method of interpretation to the rest of the new testament?
According to Wikipedia,(https://en.m.wikipedia.org/wiki/Foot_washing), the practice of foot washing used to be more common (especially in the early church). Is it fair to assume that the early church took Jesus' command literally? If so, how and why have Christians today moved to a symbolic interpretation of this passage?
Are there any exegetical hints in the original language of this passage that help us know whether Jesus is speaking metaphorically or not?
Please note: I'm not interested in this doctrine specifically or why or why not foot washing is not an ordinance in the church today. I'm more curious as to how I can know whether to interpret a specific passage in the New Testament symbolically or literally.