'Darkness' in the Bible

You came near and stood under the mountain; and the mountain burned with fire to the heart of the sky, with darkness, cloud, and thick darkness.

These words Yahweh spoke to all your assembly on the mountain out of the midst of the fire, of the cloud, and of the thick darkness, with a great voice: and he added no more. He wrote them on two tables of stone, and gave them to me.

It happened, when you heard the voice out of the midst of the darkness, while the mountain was burning with fire, that you came near to me, even all the heads of your tribes, and your elders;

and you shall grope at noonday, as the blind gropes in darkness, and you shall not prosper in your ways: and you shall be only oppressed and robbed always, and there shall be none to save you.