draw a line in the sand
To establish a figurative boundary that someone or some group refuses to cross or beyond which no further advance or compromise is accepted. I don't mind my roommate being a bit messy, but leaving dirty dishes for me to clean up is where I draw a line in the sand!
draw a line in the sand
Fig. to create or declare an artificial boundary and imply that crossing it will cause trouble. Todd drew a line in the sand by giving his roommate an ultimatum about his sloppiness—he had to start cleaning up after himself or move out.
draw a line in the ˈsand
set a limit that you refuse to allow something to go beyond: The government is trying to draw a line in the sand regarding public sector pay rises.