John 1:23, ‘I am the voice of one crying out in the wilderness, “Make straight the way of the Lord,” as the prophet Isaiah said.’
John the Baptist’s citation of Isaiah 40 is significant since, in the context of Isaiah, the one whose way is prepared is YHWH Himself. John implies, then, that he is preparing the way for the eschatological appearing of God. This makes it all the more stunning when, in just a few verses, the Baptist introduces this figure as ‘the Lamb of God, who takes away the sin of the world’ (1:29).
So, who is the Lord—who is the YHWH—for whom John is preparing the way? It is Jesus, who—critically—is introduced as ‘the Lamb of God.’ YHWH’s eschatological coming in salvation and judgment—the coming by which His glory will be made visible and His salvation will be seen (Is. 40:5)—*is* the coming of the Lamb of God who takes away the sin of the world.
But then we need to say something more, because the Baptist’s introduction of Jesus (Behold, the Lamb of God…) echoes another section of Isaiah 40, namely, v.9. There we find the content of the good news that is heralded by God’s people, and it is this: Behold your God.
The climactic message proclaimed in Isaiah 40 (the passage with which the Baptist associates himself in John 1:23) is: ‘Behold your GOD!’ and the climactic message that John proclaims is: ‘Behold, the Lamb!’ I would suggest that the Evangelist intends us to read these two ‘Beholds’ as one and the same. Isaiah’s eschatological summons to behold the God of Israel IS the Baptist’s summons to behold Jesus as the Lamb of God who takes away the sin of the world. And Is this not precisely what we find at the climax of the gospel, where Thomas—beholding the Lamb of God who stands in risen life before Him, yet as one who continually bears the marks of slaughter—beholds His Lord (YHWH) and His God (Jn 20:28)?
Yes, to Behold the Lamb aright—which is to say, to see the crucified Jesus, proclaimed in the risen Jesus, as the Lord who loves us and gives Himself for our sins—this is truly to Behold our God.
