Toe
Instead it’s about foot races!
“ The phrase means “follow the rules or obey an authority.” “Tow the line” is a misspelling based on “toe” and “tow” sounding the same, but “tow the line” is always an error. The phrase comes from the idea of standing at the starting line before a race (i.e., getting as close as possible without overstepping the mark).”
Towing the line, like you are helping to pull along the message. And towing the line like you are carrying around the lines of the message. It's too good to give up for some oddly abstracted analogy about running a race.