This wise saying starts off with a directive that is pretty straightforward and clear – “do not speak to fools.” The second line provides the rationale for it — “they will scorn your prudent words.”
The setting for this proverb would seem to be a situation where we’re trying to have a sensible discussion (“prudent words”) with people who have little capacity for it — at least at that moment (“fools).
The Hebrew term translated “fools” here doesn’t suggest mental deficiency. Instead, it’s those who are morally deficient. Their thinking and world-view has virtually no appreciation for our “prudent (understanding and insightful) words.”
It’s like a sincere conversation I tried having with a guy who was drunk last week. We were speaking to each other about the same topic — which he initiated! — but we were talking on two completely different levels.
The result of such an exchange with “fools” will be their lack of appreciation (“scorn”) for our “prudent words.” This verse suggest our conversation will be a wasted effort.
Jesus actually discussed a similar situation when he said, “do not throw your pearls to pigs. If you do, they may trample them under their feet, and turn and tear you to pieces” (Mt 7:6).
Pretty pearls laying in the slop around a pig may get eaten or just get trampled down into the mire — never to be seen again. But, maybe even worse, the pig might turn around and go after me, too!