Exodus 19:3, 20, 23

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 sons of Israel

The LORD came down on Mount Sinai, to the top of the mountain; and the LORD called Moses to the top of the mountain, and Moses went up.

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