Imagine you’re a sophomore at a Christian college. You came to the saving knowledge of Jesus Christ only three years earlier. You’re in a chapel service. The guest speaker is explaining the marvelous event we Christians call the incarnation—the conception and birth of the eternal Son of God in human flesh. “It goes a little something like this,” he says. “God came to earth and took on a human body.” While speaking, he illustrates what that process of taking on a human body must have involved by picking up his coat, which lay over a choir pew behind him, and putting it on.

Shifting scenes: you’re now in a Southern California beach city on a summer Saturday morning. Thousands of evangelical Christians have gathered for the “March for Jesus” celebration to walk through the city with praise music blaring from loudspeakers attached to the tops of vans and trucks. There are Christian T-shirts aplenty proudly worn; there’s a sense of evangelistic purpose and zeal. In the midst of the crowd, you see a group of men holding up an enormous sign on poles: “JESUS: ALL GOD IN A BOD.”

These examples from my early Christian life illustrate that every one of us, from theologian to novice, have some way of explaining what the Bible says about Jesus being both God and man, about the Son of God becoming a man. The explanations above are imprecise, unhelpful, and even incorrect ways of expressing this biblical truth. The Son didn’t wrap His eternal divinity in temporal humanity like a coat. He didn’t park His divinity in a “bod” like a car in a garage.

The Son didn’t wrap His eternal divinity in temporal humanity like a coat.

These examples are symbolic of a much larger problem within contemporary American Christianity. Just as a fish is constrained by water without knowing it, we’ve become constrained so much by our broader culture and Christian subculture that we don’t even know it.[1] The problem is that the foundational doctrines of Scripture, as understood in the history of the Christian church, are rarely taught or preached in so much of American evangelicalism.[2]

Truth be told, understanding doctrine isn’t a man-made exercise for the elite but results from obeying God’s commands to study and meditate on what He’s revealed of Himself in His Word. For example, in the Pastoral Epistles, the apostle Paul wrote to two young pastors, Timothy and Titus, exhorting them that to teach and defend creeds was to promote deeds. He emphasized the importance of doctrine, calling it:

Good doctrine (1 Tim. 4:6)

Sound doctrine (1 Tim. 1:10; 2 Tim. 4:3; Titus 2:1)

That good thing which was committed to you (2 Tim. 1:14)

The doctrine which accords with godliness (1 Tim. 6:3)

The truth which accords with godliness (Titus 1:1)

The faithful word (Titus 1:9)

The pattern of sound words (2 Tim. 1:13)

The mystery of the faith (1 Tim. 3:9)

The words of faith (1 Tim. 4:6)

Wholesome words (1 Tim. 6:3)

Doctrine, then, is simply biblical teaching that’s food for the soul like good food for the body.

Because of the New Testament’s insistence on doctrine as set forth in the Pastoral Epistles, Machen said, “The Christian movement at its inception was not just a way of life in the modern sense, but a way of life founded upon a message.”[3] The earliest Christian church’s life of love and fellowship—in which believers had “all things in common,” “sold their possessions and goods,” and shared “among all, as anyone had need” (Acts 2:44–45)—was founded on their dedication to “the apostles’ doctrine” (v. 42).

John warned his audience not to welcome certain people into their homes based on their doctrine: “Whosoever transgresses and does not abide in the doctrine of Christ does not have God. He who abides in the doctrine of Christ has both the Father and the Son. If anyone comes to you and does not bring this doctrine, do not receive him into your house nor greet him” (2 John 9–10). What we call doctrine, or theology, offers the only solid foundation on which a believer in Jesus Christ can reliably live the Christian life and face temptations and trials in their lives.

The pattern of the New Testament Epistles evidences that Christian doctrine was first proclaimed and then applied to Christian living. This is clearly the structure of the book of Romans. Paul proclaims both the doctrine of people’s sin and the doctrine of God’s salvation in chapters 1:18–11:33, and then he applies those doctrines to life in the church and in the world in chapters 12:1–15:33. Doctrine and life are inseparably united.

What we call doctrine, or theology, offers the only solid foundation on which a believer in Jesus Christ can reliably live the Christian life and face temptations and trials in their lives.

B. B. Warfield (1851–1921), the great Princeton theologian, lamented that in his day, not unlike our own, many so-called Christian theologians were rejecting the historic Christian doctrine of the two natures of Christ. This is a doctrine that teaches our Lord Jesus Christ is both God and man. Instead of this teaching, liberal Christian churches in Warfield’s day were calling for a more “relevant” Christianity. To this Warfield said, “The doctrine of the Two Natures is only another way of stating the doctrine of the Incarnation; and the doctrine of the Incarnation is the hinge on which the Christian system turns. No Two Natures, no Incarnation; no Incarnation, no Christianity in any distinctive sense.”[4]

What we call doctrine, or theology, offers the only solid foundation on which a believer in Jesus Christ can reliably live the Christian life and face temptations and trials in their lives.

So, to conclude: no doctrine = no true understanding of Christ. No understanding of Christ = no confidence in salvation. No confidence in salvation = ineffectual Christian lives.

This article is adapted from Daniel R. Hyde’s God With Us: Know the Mystery of Who Jesus Is.

1. For an entry into modern Western culture, see Charles Taylor, Sources of the Self: The Making of the Modern Identity (Cambridge, Mass.: Harvard University Press, 1989); and A Secular Age (Cambridge, Mass.: Harvard University Press, 2007).

2. On the somewhat amorphous term “evangelical/evangelicalism,” see Mark Noll, “Defining Evangelicalism,” in Global Evangelicalism: Theology, History and Culture in Regional Perspective, ed. Donald M. Lewis and Richard V. Pierard (Downers Grove, Ill.: InterVarsity Press, 2014), 17–37; Thomas S. Kidd, Who Is an Evangelical? The History of a Movement in Crisis (New Haven, Conn.: Yale University Press, 2019).

3. Machen, Christianity and Liberalism, 21.

[4. B. B. Warfield, “The ‘Two Natures’ and Recent Christological Speculation,” in Christology and Criticism, The Works of Benjamin B. Warfield (1932; repr., Grand Rapids: Baker Book House, 2000), 3:259.q