1. draw the line - Verb
2. draw the line - Phrase
reasonably object (to) or set a limit (on)
Source: WordNetWhere do you draw the line between a humble man who knows his own weaknesses but tries to act out virtues he hasn't quite mastered yet, and a proud man who pretends to have those virtues without the slightest intention of acquiring them? Orson Scott Card
People should be very free with sex, but they should draw the line at goats. Elton John
Once killing starts, it is difficult to draw the line. Tacitus
Personally, I think you can put any interpretation you want on anything, but when someone suggests that Can't Buy Me Love is about a prostitute, I draw the line. That's going too far. Paul McCartney
Who in the rainbow can draw the line where the violet tint ends and the orange tint begins Distinctly we see the difference of the colors, but where exactly does the one first blendingly enter into the other So with sanity and insanity. Herman Melville
We draw the line against misconduct, not against wealth. Theodore Roosevelt