The Lord said to Moses: “Tell your brother Aaron that he is not to come whenever he chooses into the Most Holy Place behind the curtain in front of the atonement cover on the ark, or else he will die. For I will appear in the cloud over the atonement cover.
The Lord is slow to anger but great in power; the Lord will not leave the guilty unpunished. His way is in the whirlwind and the storm, and clouds are the dust of his feet.