Isaiah 7:9 - Matthew Poole's English Annotations on the Holy Bible

Is Samaria; or rather, shall be Samaria; and the sense is the same as in the foregoing verse, Samaria shall continue to be the chief city of the kingdom of Israel, and Pekah shall not conquer Jerusalem, as he hoped and designed to do. Ye shall not be established; if you do not believe this and the other promises of God, but, in distrust of God, shall seek to the Assyrians for succour, to which I perceive you are inclined, instead of that deliverance and settlement which you expect, you shall be distressed and consumed thereby; the accomplishment of which threatening is recorded 2 Chronicles 28:20. And by this threatening he implies, that if they did rely upon God's word and help, they should be established. Only he delivereth it in the form of a threatening, rather than of promise, partly because he foresaw that they would choose the worse part, and bring the judgment threatened upon themselves; and partly because this was most necessary for them, to affright them out of their present security and infidelity.