lay down the law
Meaning: If you lay down the law, you tell people what they should do in a forceful and stern way.
- After we lost our third game in a row, our coach got really angry and laid down the law and said we had to try harder or we'd be out the door.
- Shelley's parents laid down the law after she got home late and grounded her for a month.
If someone lays down the law, they tell people what they have to do in a