en_tn/gal/04/21.md

Tell me

"I want to ask a question." The question he will ask is rhetorical. If you have to translate the rhetorical questions as statements, you can translate this "I want to tell you something." (See: rc://en/ta/man/translate/figs-rquestion)

do you not listen to what the law says?

"have you not heard what the law says?" or "you need to learn what the law really says" or "let me tell you what the law says." Paul is introducing what he will be saying in verses 22-23.