See this in your mind’s eye,
“Now the glory of the LORD rested on Mount Sinai, and the cloud covered it six days. And on the seventh day He called to Moses out of the midst of the cloud” (Exodus 24.16).
Moses had already gone up into the mountain, and then a cloud covered the mountain (Exodus 24.15). Either in the cloud, or as the cloud, was the glory of the Lord.
For six days, the cloud just covered Mount Sinai; just being a magnificent sight for Moses to experience, and for Israel from below to see, which was like a consuming fire (Exodus 24.17).
Then with calculation, God spoke to Moses and he went up into the mountain and into the cloud, and remained forty days and forty nights, not eating or drinking a thing, for it was such an awesome experience.
The God of heaven does nothing by accident, but He is a God of order and precision, and so He let His glory be on that mountain for six days for a reason, and for a reason He called out to Moses on the blessed seventh day.