'Darkness' in the Bible

and ye draw near and stand under the mountain, and the mountain is burning with fire unto the heart of the heavens -- darkness, cloud, yea, thick darkness:

These words hath Jehovah spoken unto all your assembly, in the mount out of the midst of the fire, of the cloud, and of the thick darkness -- a great voice; and He hath not added, and He writeth them on two tables of stone, and giveth them unto me.

'And it cometh to pass as ye hear the voice out of the midst of the darkness, and of the mountain burning with fire, that ye come near unto me, all the heads of your tribes, and your elders,

and thou hast been gropling at noon, as the blind gropeth in darkness; and thou dost not cause thy ways to prosper; and thou hast been only oppressed and plundered all the days, and there is no saviour.