lay down the law

lay down the law

1. To promulgate law.
   • 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.

2. (law, dated) To present the law that applies to a given case.
3. (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; 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.

• read the riot act