en_tn_lite_do_not_use/isa/48/10.md

Look, I refined you, but not as silver; I have purified you in the furnace of affliction

Yahweh speaks of using affliction to purify his people as if they were precious metals and affliction were a furnace in which he refines them. (See: rc://en/ta/man/jit/figs-metaphor)