John Trapp on Proverbs 17:3

Verſ. 3. The fining-pot is for ſilver, &c.] God alſo hath his fire in Zion, and his furnace in Jeruſalem, Iſa. 31.9. his conflatories, and his crucibles, wherein hee will refine his, as ſilver is refined, and try them as gold is tried, Zech. 13.9. Not as if hee knew them not, till hee had tried them; for hee made them, and therefore cannot but know them: As Artificers know the ſeveral parts and properties of their works. Sed tentat ut ſciat, id eſt, ut ſcire nos faciat, ſaith Auguſtin. Hee therefore tries us, that hee may make us know what is in us, what droſſe, what pure metal; and that all may ſee that wee are ſuch, as (for a need) can glorifie him in the very fires, Iſa. 84.15. that the trial of our faith being much more precious than of gold that periſheth; though tried in the fire, may bee found to praiſe, and honour, and glory, 1 Pet. 1.7.