6 Return to him from whom you have deeply revolted, children of Israel. 7 For in that day everyone shall cast away his idols of silver and his idols of gold—sin which your own hands have made for you. 8 

“The Assyrian will fall by the sword, not of man;
and the sword, not of mankind, shall devour him.
He will flee from the sword,
and his young men will become subject to forced labor. 9 His rock will pass away by reason of terror,
and his princes will be afraid of the banner,”
says Yahweh, whose fire is in Zion,
and his furnace in Jerusalem.

Matthew Henry's Commentary on Isaiah 31:6-9

Commentary on Isaiah 31:6-9

(Read Isaiah 31:6-9)

They have been backsliding children, yet children; let them return, and their backslidings shall be healed, though they have sunk deep into misery, and cannot easily recover. Many make an idol of their silver and gold, and by the love of that are drawn from God; but those who turn to God, will be ready to part with it. Then, when they have cast away their idols, shall the Assyrian fall by the sword of an angel, who strikes more strongly than a mighty man, yet more secretly than a mean man. God can make the stoutest heart to tremble. But if we keep up the fire of holy love and devotion in our hearts and houses, we may depend upon God to protect us and them.