NET
21 As the crucible is for silver and the furnace is for gold, so a person must put his praise to the test.
Darby
21 The fining-pot is for silver, and the furnace for gold; so let a man be to the mouth that praiseth him.
KJV
21 [As] the fining pot for silver, and the furnace for gold; so [is] a man to his praise.