Exodus 24:15-18

Then Moses climbed the mountain. The Cloud covered the mountain. The Glory of GOD settled over Mount Sinai. The Cloud covered it for six days. On the seventh day he called out of the Cloud to Moses. In the view of the Israelites below, the Glory of GOD looked like a raging fire at the top of the mountain. Moses entered the middle of the Cloud and climbed the mountain. Moses was on the mountain forty days and forty nights.