When you think of “spiritual signs,” you probably think of something super obvious. The sign that Gideon asked for and received from God, for example, had to do with dew on a fleece (Judges 6:36-40). When Hezekiah was given 15 more years to live, he was shown a shadow that ran counter to the normal operation of the sun (2 Kings 20:8-11).
It’s noteworthy that in Exodus 3, Moses doesn’t initially ask for a sign. He asks who he is and what makes him the right choice to go lead the people out of Egypt. In response, God gives him a sign.
But the sign that God gave Moses has an interesting twist: It’s given to him after he’s already accomplished the task.
In some ways, this is exactly like the story of Gideon and Hezekiah from earlier. In Judges 6, Gideon has already torn down the altar of Baal by the time God shows him the dewy fleece. And by the time Hezekiah’s life is extended in 2 Kings 20, he’s already demonstrated remarkable courage in resisting Sennecharib’s challenge and putting his trust in God. They were already men of some faith; the signs just amplified what they had.
The way in which Moses’ sign contrasts the other is that it doesn’t seem, at least on the surface, to be supernatural. In fact, if Moses wanted to, he could communicate the sign of “worshipping God on the mountain” to the people, then lead them there himself. There’s nothing out of the ordinary about that.
But this is a sign for Moses. It’s designed to build his faith that what he is doing is divinely appointed. What’s the point of it?
First, it reinforces the security of God’s first statement. At the beginning of Exodus 3:12, God tells Moses that He will “certainly be with [Moses].” Physical security is obviously a huge concern, so this sign is to show Moses that he will survive the trip into Egypt and back.
Secondly, it shows the nature of the deliverance. They won’t just come back to this mountain; when they get back, it’s to worship God. One glance at the Old Testament shows that this is a concept that is extremely important to God. As the Creator, He is worthy of worship, and the Israelites need to learn what that looks like.
I think a good case can be made that the sign isn’t even for Moses right then, but for later. Surely Moses knew and trusted in God before he went to Egypt (otherwise he probably wouldn’t have gone), but in order to lead the people from Sinai to Canaan, and develop them into a nation that is holy to God, he needed to be convinced of God’s authority.
That’s what the above two points outline to me. When Moses safely returned back to the mountain, he undoubtedly saw that as God’s divine protection. But when they worshipped, he saw the purpose of the trip in the first place.
With those two points in mind, he would not only lead the people through the desert, but ultimately shape them into a civilization that recognized and worshipped God for who He is.
