Exodus 24:4

24:4 and Moses wrote down all the words of the Lord. Early in the morning he built an altar at the foot of the mountain and arranged twelve standing stones – according to the twelve tribes of Israel.

Exodus 24:12-13

24:12 The Lord said to Moses, “Come up to me to the mountain and remain there, and I will give you the stone tablets with the law and the commandments that I have written, so that you may teach them.” 24:13 So Moses set out with Joshua his attendant, and Moses went up the mountain of God.

Exodus 24:18

24:18 Moses went into the cloud when he went up the mountain, and Moses was on the mountain forty days and forty nights.