כִּֽי־בְחַנְתָּ֥נוּ אֱלֹהִ֑ים צְ֝רַפְתָּ֗נוּ כִּצְרָף־כָּֽסֶף׃
For Thou, O God, hast tried us; Thou hast refined us, as silver is refined.
Rashi on Psalms
You refined us to remove the dross from us when we repent before You, as they refine silver to remove its dross.