Isaiah 7:14, “Therefore the Lord himself will give you a sign. Behold, the virgin shall conceive and bear a son, and shall call his name Immanuel.”
Matthew quotes this verse of Isaiah to prove the prophecy of the virgin birth. However, the context of Isaiah seems to imply a more immediate fulfillment in the life of Isaiah. Biblical prophecy is often fulfilled by what is called typology. Typology is a way of interpreting the Bible using types. A person or event later in history is a type of a previous person or event. For example, the return from exile of the people of Israel from Babylon is a type of the Exodus from Egypt. God repeats things throughout history and uses the previous event to help explain the later event. So the return from exile is like the Exodus in that it saves God’s people from captivity, but also had an ultimate fulfillment in Christ by saving us from our captivity to sin.
The child being born to a virgin is similar. The promise had an immediate fulfillment in the son Maher-shalal-hash-baz. The child would be a reminder of God’s promise to save the city of Jerusalem. However, the ultimate fulfillment of this prophecy is in the birth of another son, Jesus. He will save not just the city of Jerusalem from the Babylonians, but will save all God’s people from their sin. And this son will not just be a reminder that God was with His people when He saved the city. This Son will truly be Immanuel. He will be God incarnate. He will truly be “God with us”.