John Gills Exposition of the Bible Commentary

Verse 21 (Proverbs 27:21)

As the fining pot for silver, and the furnace for gold ,.... For the trying, proving, and purifying these metals; see Proverbs 17:3 ;

so is a man to his praise ; or "according to the mouth of his praise" F16 לפי מהללו "ad os laudis suae", Gejerus. ; if his own mouth praises him, as in Proverbs 27:2 ;, he is known to be what he is, a foolish and vainglorious person: or "so a man is proved by the mouth of him that praises him", as the Vulgate Latin version; or "of them that praise him", as the Septuagint, Syriac, and Arabic versions; and so the Targum: the meaning is, either a man is known by the persons that praise him, according to what their characters are; if he is praised by good and virtuous men, he may be thought to be so himself; and if by wicked men, he may be concluded to be so likewise; see Proverbs 28:4 ; or he is known by the effect that praise has upon him; if it swells him with pride, and makes him haughty, conceited, and overbearing, he will appear to be a weak and foolish man; but if he continues modest and humble, and studious and diligent to answer his character, thankful to God for what he has, and to whom he gives all the glory, he will approve himself a wise and good man.

- John Gills Exposition of the Bible Commentary