27 Whoever restrains his words has knowledge, and he who has a cool spirit is a man of understanding. 28 Even a fool who keeps silent is considered wise; when he closes his lips, he is deemed intelligent. (Proverbs 17:27–28, ESV)
Possessing the ability and the discernment to control one’s words is a mark of wisdom. This is verified in James 1:19, “let every man be slow to speak…” Keeping one’s cool instead of spouting off when agitated reveals a prudent soul. You do not have to always say something in order to prove you are knowledgeable on a matter. Often it is when we open our mouths that we remove all doubt of whether we are foolish. Choose your words carefully. See the value of saying nothing if, by speaking, you merely reveal your lack of understanding.