One could hardly overestimate the importance of Isaiah 40–66 for understanding the work of Jesus. Many are likely familiar with Isaiah 53 and its very clear prediction of our Savior’s death and resurrection. The entire second half of Isaiah is vital, however, for comprehending Jesus’ mission. Luke’s gospel makes this particularly clear, for Luke 3–4 quotes significant portions of Isaiah 40–66 to help explain the purpose of our Lord’s coming.
Today’s passage quotes from Isaiah 40:1–5, explaining that John the Baptist’s preaching of repentance fulfills this text (Luke 3:4–6). Here it is important to consider Isaiah in his original context. Isaiah 1–39 focuses much on the failures of the southern kingdom of Judah, and it concludes by noting that the sins of King Hezekiah, one of the most righteous old covenant monarchs, meant that the Babylonian exile was sure to come. The rot was so deep that even Hezekiah at times did not fully trust the Lord but put his hope in earthly powers—such as Babylon—to come to the aid of Judah (Isa. 39). But Isaiah’s message does not end with chapter 39. The prophet goes on in chapters 40–66 to foresee Judah’s return from exile and the work of the Messiah to end the war between God and His people and purchase their forgiveness. Judah’s rescue from Babylon and restoration to the promised land is described as an event with cosmic significance, for Isaiah says that a new creation would come when Judah finally returned home (Isa. 65:17–66:24; see Isa. 25).
In 538 BC, after conquering Babylon, King Cyrus of Persia decreed that the Jews could return to their homeland (2 Chron. 36:22–23). Yet the glorious prophecies of the new heaven and earth did not come to pass at that time, and the Jews remained under the authority of a succession of empires from the Persians to the Greeks to the Romans. They kept waiting for the full and final return from exile.
By applying a prophecy about the return from exile to the ministry of John the Baptist (Luke 3:4–6), Luke is making the point that the final redemption of the world for which the Jews waited was about to arrive. God was coming to set everything right and bring a blessing to His people that would redound to the whole world. The Jews would be redeemed from the sin that had led to their exile from their homeland, and ultimately all who trust in the God of Israel will be rescued from the very first exile, our being cast out of the Lord’s blessed presence in Eden because of Adam’s sin (see Gen. 3:22–24).