Exodus 19:3, 20, 23

And Moses went up to God, and the LORD called to him from the mountain, saying, “Thus you shall say to the house of Jacob, and tell the children of Israel

Then the LORD came down upon Mount Sinai, on the top of the mountain. And the LORD called Moses to the top of the mountain, and Moses went up.

But Moses said to the LORD, “The people cannot come up to Mount Sinai; for You warned us, saying, ‘Set bounds around the mountain and consecrate it.’ ”