As Moses recounts the incident with the golden calf, he reminds Israel that he ground the idol to powder and threw it in the “brook ( nachal ) that came down from the mountain” (Deuteronomy 9:21).
There was a brook in Egypt (Numbers 34:5), the Nile that watered the land and made it the breadbasket of the ancient world. In the face of grumblers who wanted to return to Egypt, Yahweh made the wilderness well-watered like Goshen.
There were going to be brooks in the land of promise (Deuteronomy 10:7). By bringing water from the rock, Yahweh made the wilderness a pledge of Israel’s inheritance.
And every time the rains filled the wadis of the Canaan’s valleys, Israel was reminded of the miracle of the wilderness. Every brook was another water miracle, a memorial of the brook from the mountain.