Ezekiel may have used the term “mountains of Israel” as a deliberate contrast to the plains that characterize the land of Babylon. More likely, however, he is using the term to refer to the whole of the land of Israel which had “altars on every high hill and on all the mountaintops” (v. 13). This was in deliberate violation of the commandment to destroy all such Canaanite sanctuaries with their grossly immoral religion and to worship Yahweh alone (Dt 12:1-7). All such shrines, whether on mountains or in the valleys, would be destroyed. Those who worshiped at these pagan shrines would discover that the gods at these shrines could not protect them against the wrath of Yahweh (6:4).
It is a mistake, however, to see God's judgment and the Exile only as an expression of God's wrath. Indeed, in his heartbreak, God said, “I have been grieved by their adulterous hearts” (v. 9), and yet he would spare some (v. 8). These would be taken into exile where its discipline would bring them to repentance. The purpose of the Exile was that the remnant would again “know . . . the Lord” (vv. 10, 14). “To know” often means to have an intimate or experiential relationship with someone. So the Exile too was an expression of the covenant loyalty and steadfast love (ḥesed) of God. His love never lets us go.