lay down the law

present singular third person lays down the law · participle present laying down the law · participle past laid down the law · past laid down the law

1. To promulgate law.

   Six or eight thousand years ago / They laid down the law / In Mesopotamia

   1982, “Mesopotamia”, performed by The B-52's

   1 more example

   [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.

   2004, John Lierman, The New Testament Moses, page 125

2. datedlawTo present the law that applies to a given case.
3. idiomaticTo authoritatively or dogmatically assert what is permitted or not permitted.

   Looks like the governor's laid down the law about the guards getting too lax, so we have to be damned careful.

   2003, Robert Ludlum with Gayle Lynds, The Altman code, page 357

   2 more examples

   He concluded this sentence with a self-important cough, as one who has laid down the law in an indisputable manner.

   1818, Sir Walter Scott, The Heart of Mid-Lothian, chapter 4

   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.

   1908, Upton Sinclair, The Moneychangers, chapter 19