“And you, son of man, prophesy to the mountains of Israel and say: O mountains of Israel, hear the word of the LORD.
The prophet had been ordered to set his face towards the mountains of Israel and prophesy against them, Eze 6:2. Then God was coming forth to contend with his people; but now that God is returning in mercy to them he must speak good words and comfortable words to these mountains, Eze 36:1 and again Eze 36:4.
Commenting on Ezekiel 36:1-15
Also, thou son of man, prophesy unto the mountains of Israel,.... The land of Judah, which was very mountainous, at least one part of it, called the hill country, Luk 1:39 and now the country being cleared of men through the captivity, and other desolating judgments, there were none but bare mountains to speak unto: or, "prophesy concerning the mountains of Israel" (d); the inhabitants...
Prophesy unto the mountains of Israel - This is a part of the preceding prophecy though it chiefly concerns the Jews. In it they are encouraged to expect a glorious restoration, and that none of the evil wishes of their adversaries should take place against them.