Ahaz, the King of Judah, is terrified by the threat of invasion. Isaiah calls on him not to fear but to trust God who will deal with his enemies, and God offers a sign as assurance. Ahaz rejects God's gracious offer and trusts in Assyria instead! So, God rejects Ahaz, and yet still gives a sign which involves the birth of a son to a virgin who is Immanuel. God with us.