Where is Mt Sinai?
Paul describes Mt. Sinai as being in Arabia.
Galatians 4:25 “Now Hagar stands for Mount Sinai in Arabia and corresponds to the present city of Jerusalem, because she is in slavery with her children.”
When Moses first left Egypt, he fled to Midian where he eventually encountered God on Mt. Sinai, also called Horeb, the mountain of God.
Exodus 3:1 Now Moses was tending the flock of Jethro his father-in-law, the priest of Midian, and he led the flock to the far side of the desert and came to Horeb, the mountain of God. 2 There the angel of the LORD appeared to him in flames of fire from within a bush. Moses saw that though the bush was on fire it did not burn up.
That’s where God tells Moses He wants him to free His people. God told Moses to bring the Israelites back to worship Him on this mountain.
Exodus 3:12 And God said, “I will be with you. And this will be the sign to you that it is I who have sent you: When you have brought the people out of Egypt, you will worship God on this mountain.”
Amplified Bible: Exodus 3:12 “God said, I will surely be with you; and this shall be the sign to you that I have sent you: when you have brought the people out of Egypt, you shall serve God on this mountain [Horeb, or Sinai].”
Acts 7:30, 38
30 “After forty years had passed, an angel appeared to Moses in the flames of a burning bush in the desert near Mount Sinai.
38 He was in the assembly in the desert, with the angel who spoke to him on Mount Sinai, and with our fathers; and he received living words to pass on to us.
Comparing the Old Testament passages with the New Testament passages, we can see that Sinai and Horeb are the same mountain.
The Mt. Sinai of Moses could not possibly be in the Sinai Peninsula because Moses was tending the flock of Jethro in Midian when God spoke to him there (Mt. Sinai). We know where Midian is today. It's the same place as it was then: Western Arabia.