The Lord said to Moses, Say to Aaron, your brother, that he may not come at all times into the holy place inside the veil, before the cover which is on the ark, for fear that death may overtake him; for I will be seen in the cloud on the cover of the ark.
The Lord is slow to get angry and great in power, and will not let the sinner go without punishment: the way of the Lord is in the wind and the storm, and the clouds are the dust of his feet.
And you came near, waiting at the foot of the mountain; and flames of fire went up from the mountain to the heart of heaven, with dark clouds, and all was black as night.