lay down the law
Verb
Meaning
To promulgate law.
(law, dated) To present the law that applies to a given case.
(idiomatic) To authoritatively or dogmatically assert what is permitted or not permitted.
Source: en.wiktionary.orgSynonyms
pontificate
dictate
domineer
call the shots
dogmatize
push around
boss around
lord it over
call the tune
Examples
An older family member might lay down the law today.
It is time we lay down the law on hate speech!