הִנֵּ֥ה צְרַפְתִּ֖יךָ וְלֹ֣א בְכָ֑סֶף בְּחַרְתִּ֖יךָ בְּכ֥וּר עֹֽנִי׃
Behold, I have refined thee, but not as silver; I have tried thee in the furnace of affliction.
Read Jewish philosophy on Isaiah 48:10: Rambam's Guide for the Perplexed, Saadia Gaon, and classical Jewish philosophical sources, free online.