What does Proverbs 27:21 mean?

Intense heat tests the quality of gold and silver. Refiners melt these metals to reveal impurities which can then be removed. Solomon (Proverbs 25:1) applies this idea of testing to praise, using it to measure a man. Commentators take this in one of two ways.

The first interpretation is that subjecting a man to praise is like placing precious metals in a crucible. How that person reacts reveals their purity and true nature. The one who responds to compliments with arrogance or egotism reveals character flaws. The person who accepts praise with humility shows no such errors. The apostle Paul demonstrated this correct response to excessive adoration from other men. When he and Barnabas healed a man at Lystra, the crowds suggested they were gods. Paul and Barnabas rejected that claim. They were simply men with good news. Paul followed the rejection of inappropriate praise with a clear message about God and His goodness (Acts 14:8–17). Paul quotes Jeremiah 9:24 in 1 Corinthians 1:31: "Let the one who boasts, boast in the Lord." In Galatians 6:14 he writes, "But far be it for me to boast except in the cross of our Lord Jesus Christ, by which the world has been crucified to me, and I to the world."

The second interpretation is that man can be judged by what he praises. Character is revealed by what a person applauds or enjoys (Isaiah 5:20; Romans 1:32; 14:22). Silver and gold reveal their hidden flaws when placed in a furnace. So too does a man uncover his tastes and priorities by the things he compliments.