Isaiah 7-9…Old Testament typology.
Scripture clearly teaches that God is “unchangeable in his being” (Mal. 3:6), and one consequence of the Lord’s immutable character is that His ways are consistent throughout history. For example, God’s use of Moses to rescue His people from Egypt is not the only exodus Scripture records (Ex. 3). The prophets also describe Israel’s restoration after the exile as a new exodus (Isa. 11:16; Ezek. 20:33–38). Furthermore, the New Testament sees Jesus’ ministry as the final exodus (Matt. 2:13–15; 1 Cor. 5:7).
Knowing that God works in similar ways in every generation helps us interpret Old Testament prophecy. The historical context of Isaiah 7 tells us the sign of Immanuel had meaning for eighth-century BC Judah. This sign had a fulfillment then in the birth of Isaiah’s son because Israel’s and Syria’s threat had to end within that generation, as it was tied to Assyria’s invasion of Judah in 701 BC during King Hezekiah’s reign (Isa. 7:10–17; 8:3–4; 36–37). In fact, Israel and Syria no longer threatened Judah after 732 BC.
Thus, Matthew’s citation of Isaiah 7:14–17 does not necessarily mean the Apostle thought it was a direct vision of Jesus’ birth (Matt. 1:18–25). Instead, it seems that Matthew saw similarities between the first century AD and Ahaz’s era that told him God was acting in a manner analogous to but greater than what He did in Isaiah’s day. A foreign enemy (Rome) threatened Judah in the first century, just as foreign enemies (Syria and Israel) had threatened Judah centuries earlier. Mary conceived a son just as Isaiah’s wife did in the eighth century BC (Isa. 8:3–4), only the virginal conception of Jesus was a greater miracle (Matt. 1:18–25; Luke 1:26–38). Moreover, Ahaz’s rejection of the sign in Isaiah 7 led to Judah’s later devastation, just as Jerusalem fell to Rome in AD 70 after the Jewish leaders rejected Jesus (Matt. 24:15–31; 26:56–68).
Matthew’s discovery of these analogical connections is known as typology, which was the Apostles’ favorite way to read the Old Testament. They did not read secret meanings into the prophets (allegory); rather, they saw how God was fulfilling His covenant promises during the first century in a manner that had precedent. God’s earlier dealings with Israel hinted that there was more to come. Since Assyria devastated Judah for its sin during the eighth century BC (Isa. 8), a better Immanuel was needed— God with us to such a degree so as to destroy evil once and for all (1 John 3:8).