For thus hath the LORD spoken unto me, Like as the lion and the young lion roaring on his prey, when a multitude of shepherds is called forth against him, he will not be afraid of their voice, nor abase himself for the noise of them: so shall the LORD of hosts come down to fight for mount Zion, and for the hill thereof. As birds flying, so will the LORD of hosts defend Jerusalem; defending also he will deliver it; and passing over he will preserve it. Turn ye unto him from whom the children of Israel have deeply revolted. For in that day every man shall cast away his idols of silver, and his idols of gold, which your own hands have made unto you for a sin. Then shall the Assyrian fall with the sword, not of a mighty man; and the sword, not of a mean man, shall devour him: but he shall flee from the sword, and his young men shall be discomfited. And he shall pass over to his strong hold for fear, and his princes shall be afraid of the ensign, saith the LORD, whose fire is in Zion, and his furnace in Jerusalem.
God is likened to a lion which a multitude of shepherds, Assyria, tried to frighten away and to a flock of birds, hovering over Jerusalem; He is ready to defend and deliver the city. When Israel turns back to the Lord, it will throw away its idols. The Assyrians will perish by a direct intervention of the Lord. The destruction of Sennacherib did not exhaust the meaning of these verses, so the prophecy has a future fulfillment as well, that is, in the Tribulation.