lay down the law

English

lay down the law (third-person singular simple present lays down the law, present participle laying down the law, simple past and past participle laid down the law)

To promulgate law.
- 1982, “Mesopotamia”, performed by The B-52's:
  Six or eight thousand years ago / They laid down the law / In Mesopotamia
- 2004, John Lierman, The New Testament Moses, page 125:
  [I]n other words, some Jews thought of Moses as the one who laid down the Law, while others saw him more as a prophet.
(law, dated) To present the law that applies to a given case.
(idiomatic) To authoritatively or dogmatically assert what is permitted or not permitted.
- 1818, Sir Walter Scott, The Heart of Mid-Lothian, chapter 4:
  He concluded this sentence with a self-important cough, as one who has laid down the law in an indisputable manner.
- 1908, Upton Sinclair, The Moneychangers, chapter 19:
  Montague could picture the grim, hawk-faced old man, sitting at the head of the council board, and laying down the law to the masters of the Metropolis.
- 2003, Robert Ludlum with Gayle Lynds, The Altman code, page 357:
  Looks like the governor's laid down the law about the guards getting too lax, so we have to be damned careful.

to assert what is permitted