15 And Moses went up to the mount, and the cloud covered the mount.
Exodus 24:15 Cross References - Leeser
Exodus 19:9
9 And the Lord said unto Moses, Behold, I will come unto thee in a thick cloud, for the sake that the people may hear when I speak with thee, and that also in thee they shall believe for ever; and Moses told the words of the people unto the Lord.
Exodus 19:16
16 And it came to pass on the third day when it was morning, that there were thunders and lightnings, and a heavy cloud was upon the mount, and the voice of the cornet was exceedingly loud; so that all the people that were in the camp trembled.
2 Chronicles 6:1
1 Then said Solomon, “The Lord said that he would dwell in the thick darkness.