Draw a line in the sand

Meaning

To set a firm boundary or establish a final position that one refuses to cross. It serves as a warning that there will be consequences if the boundary is ignored.

Assertive, firm

Used in a sentence

• I had to draw a line in the sand regarding overtime pay.
• She drew a line in the sand and told him he had to stop being late.
• The board drew a line in the sand and refused to negotiate further.