“God became man so that man might become god.”

In his introduction to On the Incarnation, famed 20th century author and theologian Clive Staples Lewis writes, “Every age has its own outlook. It is specially good at seeing certain truths and specially liable to make certain mistakes. We all, therefore, need the books that will correct the characteristic mistakes of our own period. And that means the old books.” He suggests that a good reading habit is to alternate between the old and new—delving into one book from an earlier time for each trendy one that you read. This advice seems particularly appropriate when it comes to matters of orthodox theology and doctrine, but unfortunately the evidence indicates that it has not been heeded at all.

I believe that many who find that “nothing happens” when they sit down, or kneel down, to a book of devotion, would find that the heart sings unbidden while they are working their way through a tough bit of theology with a pipe in their teeth and a pencil in their hand. — C.S. Lewis

There are a number of objectionable beliefs and practices that used to be fringe but are currently holding sway in Christian circles. The curious thing, though, is that almost none of them are new. They’ve cropped up before, hundreds or thousands of years ago, and been roundly refuted and condemned as heresies. But since we as a society mostly don’t read old books (or, any books at all, to be honest) we simply don’t know. In this way, large swaths of people are prone to fall under the influence of Christian leaders who think they’ve uncovered some profound new teaching when they’ve really only dusted off an age-old heresy. Many Christians have heard the names of these heresies, even if they don’t know what they entail—Marcionism, Montanism, (semi-)Pelagianism, Gnosticism. Because the modern Christian is unfamiliar with these heresies, they don’t realize that the teachers they learn from often affirm them.

In our time, there is a central doctrine that faces attacks on both sides—the dual nature of Christ. That Jesus Christ was both fully divine and fully human is the accepted teaching, however hard that is to wrap one’s head around. But there are many who claim that Jesus was only one or the other. Luckily for us, there’s an old book that addresses this issue—Athanasius’s On the Incarnation.

Athanasius is revered for his work on clarifying the doctrine of the Trinity, combating the heresy of Arianism, and contributing to the canonization of the Bible. His lifelong opposition to the teachings of Arius—who taught that Jesus was a created being, not co-eternal with God the Father—got him exiled from his bishopric five times and earned him the nickname “Athanasius Against the World.” But before that lengthy kerfuffle, he was just an earnest young Christian who wrote a letter to his friend explaining the reasoning behind the doctrines that he held to. It just so happens that that letter turned out to be a classic of the Christian tradition.

Although On the Incarnation is relatively short, it covers quite a lot of ground. Athanasius begins at the beginning, with the origins of the universe. He addresses several prominent conceptions of the time—such as everything being its own cause, or that a lesser version of God created the universe from pre-existing matter—before putting forth his view of creation ex-nihilo. Man was made in the image of God, but the very first of us, Adam, fell into sin, became conscious of his own corruption, and hid from God. Death was the result of such disobedience, and yet God did not wish to destroy his rational, image-bearing creations. Instead he chose the Incarnation. That is, rather than give us over to our corruption and let us suffer for rejecting Him, the Logos—the very Word by which the universe was created—took upon himself the nature and flesh of humanity in order that He might redeem it. (Athanasius often frames his discussions as if God was uncertain what to do, or stuck in a conundrum somehow. I don’t know whether this was how he conceived of it or simply a way for making his writing more dramatic. But it’s not the conventional understanding of how God operates. It’s a nit that I’m picking at, but thought it was worth noting.)

Life without the knowledge of God is ultimately devoid of purpose and meaning. Even secular philosophers, when trying to formulate atheistic moral systems, end up circling back to theistic frameworks. It’s the only way to make sense of things. In some sense, we all have innate knowledge of God, even if we often choose to reject that knowledge in favor of following our own damaged wills. Athanasius sees such a choice as irrational, but that is what man did, rejecting God in favor of idols, witchcraft, and astrology. Despite the beauty of creation and His revelations to the prophets recorded in the Hebrew Bible, man fell into corruption and could not claw his way out on his own. The only way, then, for man to be returned to his original state of unity with God was through the redemption of his corrupted flesh. To accomplish this, the Logos became human; became Jesus Christ, the God-man. His life, miracles, and teachings endorse his deity, while his public and dishonorable death reinforces his humanity. It is the resurrection in His uncorrupted body that is the pinnacle of the gospel message—victory over sin and death.

The death of all was consummated in the Lord’s body; yet, because the Word was in it, death and corruption were in the same act utterly abolished.

Athanasius cites Scripture frequently to support all of his points, which is effective if one already believes the Bible to be the inspired Word of God. An especially moving section is when he traces 1 Corinthians 15:55 (“Where, O Death, is your victory? Where, O Death, is your sting?”) forward to the early Christian martyrs who were willing to die rather than apostatize. It really speaks to the softness of pop-Christendom today, which is largely composed of people who have never experienced serious persecution for their faith.

There are two more sections, directed toward unbelieving Jews and Greeks. Of particular interest in the portion written to unbelieving Greeks is the idea that if one considers it possible that God can act in His creation at all, one should not scoff at the idea of Him choosing the flesh of man to do that. Impossible to convey in a short review of the book is the deft hand with which Athanasius addresses his audience. Whether he is addressing Platonists, Epicureans, Jews, or Greeks, he skillfully sketches out a common ground of shared understanding before guiding the discussion toward the necessity of the Incarnation.

If I must critique such a monumental and historically significant apologetic work, I would take issue with one of Athanasius’s proofs for the verity of the resurrection of Christ. He posits that the fact that many nations were converting to Christianity is proof of the truth of his claims. I find this unconvincing because, as the author spent some time elaborating, man is corrupted and often makes incorrect choices. He wrote in a time when Christianity had just swept across the Roman Empire, and Constantine was about to decriminalize it; but that doesn’t mean all those people couldn’t have been fooled into believing something false. In the 21st century, it’s all too easy to point to other religions, both theistic and secular, that have swept across societies in the blink of an eye.

Although Athanasius lived in a time when Christianity was growing rapidly, there was plenty that could have tampered his enthusiasm if he wished to let it. You may not have noticed, but modern American Christians do not have to face the possibility of being fed to lions (at least, not yet). It’s easy for us to sit back in our comfy chairs and pine for those days when Christianity was marked more by its unity than by its thousands of denominational strains; when Athanasius is joyfully speaking of victory over idols, demons, and death, our cynical modern sensibilities are predisposed to scoff—“if only he could see the state of the world now!” But things were pretty bad in Athanasius’s time too. But to be clear, his enthusiasm isn’t misplaced. He put his trust in Christ and was seeing the world transform before his eyes, the new flower of the Church blossoming from the dry ground of the pre-Christian world. His passion was warranted then and is still warranted now, despite all the evils still at large.