the Lord came

Exodus 19:11
and be prepared by the third day, for on the third day the LORD will come down on Mount Sinai in the sight of all the people.

Nehemiah 9:13
You came down on Mount Sinai, and spoke to them from heaven. You gave them just ordinances, true laws, and good statutes and commandments.

Psalm 81:7
You called out in distress, and I rescued you; I answered you from the cloud of thunder; I tested you at the waters of Meribah. Selah

Moses went up

Exodus 19:3
Then Moses went up to God, and the LORD called to him from the mountain, "This is what you are to tell the house of Jacob and explain to the sons of Israel:

Exodus 24:12, 13, 18
Then the LORD said to Moses, "Come up to Me on the mountain and stay here, so that I may give you the tablets of stone, with the law and commandments I have written for their instruction." . . .

Exodus 34:2, 4
Be ready in the morning, and come up on Mount Sinai to present yourself before Me on the mountaintop. . . .

Deuteronomy 9:9
When I went up on the mountain to receive the tablets of stone, the tablets of the covenant that the LORD made with you, I stayed on the mountain forty days and forty nights. I ate no bread and drank no water.