Proverbs 27:21 - Ellicott's Commentary On The Whole Bible

So is a man to his praise — i.e., as the fining-pot and furnace test the metals put into them, so does that on which a man prides or boasts himself. Observe what this is — e.g., wealth, or show, or popularity, or duty — and you will see what sort of a man he is. Or it may mean, praise — i.e., popularity, is as great a trial to a man as the fining-pot to silver; he must be of good metal if he comes unhurt out of this. Or, again, it may signify, let a man test his praise — i.e., examine by whom and for what he is praised, and be sure it is genuine and well deserved