Proverbs 27:21

As the fining pot for silver, and the furnace for gold; so is a man to his praise.
– Proverbs 27:21

The fining pot and furnace are not analytical tools for testing metal, but rather instruments of refining and preparing metal. Metal is tested in the crucible, and that is a common enough image of men being tested by trials, but it doesn’t end there. Metal is purified in the crucible and made ready for use. Likewise, praise tests and purifies a man, or else it tests and discards him. Wisdom warns against self-praise (Proverbs 17:3; 25:27; 27:2).