The Lord said to Moses: Speak to Aaron your brother so that he does not come at any time into the Holy Place within the veil before the mercy seat, which is on the ark, so that he will not die, for I will appear in the cloud on the mercy seat.
the Lord is slow to anger and great in power, and the Lord will in no way acquit the guilty. In gale winds and a storm is His way, and clouds are the dust of His feet.
Then you came near and stood at the foot of the mountain, and the mountain burned with fire up to the midst of heaven, with darkness, a cloud, a thick cloud.