if knows what's good for

if somebody knows what's good for them

if you say that someone will do something if they know what's good for them, you mean that they should do that thing or else something bad might happen to them You'll obey my orders if you know what's good for you.

Common Names:

Name	Pronounced	Usage
Binyamin	bee-nyah-MEEN (Jewish)	Hebrew, Arabic, Biblical Hebrew
Satchel	SACH-əl	English (Rare)
Rosa (1)	RO-sah (Spanish, Dutch), RAW-zah (Italian), RO-zə (English)	Spanish, Italian, Portuguese, Swedish, Norwegian, Danish, Dutch, German, English
Felina	-	Late Roman
Yazhu	-	Chinese
Thoma	-	Old Church Slavic