Isaiah 7:4-6, 14

Tell him to stop worrying. Tell him he doesn’t need to fear the fierce anger of those two burned-out embers, King Rezin of Syria and Pekah son of Remaliah. Yes, the kings of Syria and Israel are plotting against him, saying, ‘We will attack Judah and capture it for ourselves. Then we will install the son of Tabeel as Judah’s king.’

All right then, the Lord himself will give you the sign. Look! The virgin will conceive a child! She will give birth to a son and will call him Immanuel (which means ‘God is with us’).