en_tn_lite_do_not_use/jhn/01/26.md

This is the one who is coming after me.

"He will preach to you after I am gone."

I am not worthy to untie the strap of his sandal

John is saying that he does not deserve to do the most unpleasant work of a servant. (See: rc://en/ta/man/translate/figs-metaphor)