There comes a time when you have to draw a line that sets apart what you’re willing to live with and what you’re determined to live .
It’s a subtle line and perhaps only you can see it. Yet it makes all the difference between your life directed and your life diverted.
Thank you for practising,
Genju
108zenbooks 
This is a very clear teaching. For me, the line requires two things: “drawing” the line in a way that is clear and responsible (for example, no more alcohol) and also moment-to-moment awareness of mind’s function around the line. ‘Cause, given my particular mind, it always tries to skirt around the line, probing and testing, jumping and tunneling. Darn mind.
yes, it’s about intention, isn’t it. sometimes I just slide around on the surface of life without examining, what is my intention here. No line, just a lot of fogginess. A sure cause for misunderstandings and suffering.
Barry’s comment is interesting to me too. It reminds me of something my Zen teacher used to say “we are delinquent types” meaning we often try to find circumstances where the “drawn” line doesn’t apply to me, at this moment, in this place. We try and wiggle under it, around it.