'Thick' in the Bible

Then they will look to the earth, they will see only distress and darkness, the gloom of anguish; and they will be driven away into darkness and overwhelming night.

Now look, the name of the Lord comes from far away,Burning with His anger, and heavy with smoke;His lips are full of indignation,And His tongue is like a consuming fire.

“I have wiped out your transgressions like a thick cloudAnd your sins like a heavy mist.Return to Me, for I have redeemed you.”