Ezekiel 24:9-12

“ ‘So this is what the Lord GOD says: How terrible it will be for the city of murderers! I myself will pile the wood high for burning. Pile up the wood and light the fire. Finish cooking the meat. Mix in the spices, and let the bones burn. Then set the empty pot on the coals so it may become hot and its copper sides glow. The dirty scum stuck inside it may then melt and its rust burn away. But efforts to clean the pot have failed. Its heavy rust cannot be removed, even in the fire.