Prov 17:28 “Even a fool, when he keeps silent, is considered wise; when he closes his lips, he is counted prudent.”
This reminds me of a story, I think it was told by Hubert Humphrey on himself. When asked if he could speak to a group, he asked how long a message they would like him to give because he would need time to prepare. He said if they wanted him to speak for 5-10 minutes, it would take him a couple weeks to prepare. If they wanted him to speak for 30 minutes it would take a week to prepare. If they wanted him to speak for an hour, it would take at least a day or so to prepare. But if they wanted him to speak for at least two hours he said he was ready to go right now.
I think the Bible has some pretty good advice.