Machen himself observed that the substitutionary atonement assumes the uniqueness of Christ’s person. Our estate of sin is so great that no mere man could ever pull us out of the depths of its quagmire. We do not need only a model or a teacher; we need a Savior. As Machen asserted, “Jesus is no mere example for faith, but the object of faith.” We do not need a mere man to save us, but we do need a true man to save us. We need one who is truly God and truly man. We need Jesus Christ. That was true in Machen’s day, and it remains true in our day.
One of J. Gresham Machen’s emphases in Christianity and Liberalism is the need to understand Jesus rightly. As a devoted churchman and astute scholar, Machen was well informed about unorthodox views of Jesus both in the church and in the academy, and the same errors often arise in our own day. Today, Jesus is often spoken of in scholarly literature as a Jewish prophet from Nazareth who was also, in some respect, the Son of God—but this is not always understood as the divine Son of God. It is often assumed that Jesus of Nazareth was a human person about whom we can say much, whereas to speak of Him as the divine Son of God would be too speculative. But here we must be careful, for orthodox Christology warns that it would be quite mistaken to think of Jesus simply as a person from Nazareth. At the same time, it would also be wrong to deny the true humanity of Jesus, which is also a nonnegotiable for orthodox Christology. To navigate these tricky waters requires us to articulate the doctrine of Christ appropriately.
Thankfully, we have many hundreds of years of faithful, biblical reflection in the church’s great creeds to draw upon to help us think rightly about Christ. To begin, we must understand that to speak of Christ is to speak of the second person of the Trinity: the eternal Son of God. It is this divine Son of God, this divine person, who is the person we encounter in the incarnation. It would therefore be incorrect to speak of Jesus Christ as if we were encountering a human person from Nazareth. It would also be incorrect to think of two persons in the incarnation—as though in the incarnation we met both a divine person and a human person. Instead, Jesus Christ is one person—a divine person who has taken on a human nature. Though He was born in Bethlehem and raised in Nazareth according to His human nature (Matt. 1:18–23; Luke 2:1–14), His true origins are eternal (see Mic. 5:2), for He is the eternal Son of God.
This requires us to understand rightly what is often known as the hypostatic union (see Westminster Confession of Faith 8.2). The hypostatic union teaches that in the incarnation, two natures (divine and human) are united in the one person of Christ. The term hypostasis (from which the term hypostatic comes) refers to a divine person, and union refers to the union of the divine and human natures in the one person. This means that in the incarnation, Christ retains His divine nature while also taking on (or assuming) a human nature. Yet these natures are not in any way confused, changed, divided, or separated, but they are united in the one person of Christ. Neither do the natures act on their own, but it is always the person of the Son of God who acts.