Leahy’s method is well worth considering anew. And we’d also do well to heed his reminder that “the worship of the Triune God through the risen Christ, and the proclamation of Christ’s victory, are always infinitely stronger than all demonic forces in their strongest combinations” (172). Satan Cast Out is a biblically sound survey of demonology that can equip pastors and church leaders to deal with the rising tide of spiritualism and the occult.

Editors’ note: 

Taking the advice of C. S. Lewis, we want to help our readers “keep the clean sea breeze of the centuries blowing through our minds,” which, as he argued, “can be done only by reading old books.” To that end, our Rediscovering Forgotten Classics series surveys some forgotten Christian classics that remain relevant and serve the church today.

As a friendly neighborhood angelologist, I periodically field calls about supernatural encounters. For example, a group of students recently approached me with some questions spurred on by their experiences on a disaster relief trip to North Carolina. While staying at a vacant building during the trip, some of the students had some uncanny, bizarre experiences. Was it demons? What could demons do anyway?

During such moments, when people are scared or confused or just plain weirded-out, folklore and superstition often step in and complicate matters all the more. Naturally, that leads to a confusion between biblical teaching and cultural narratives. The students and I were able to have a great conversation about spiritual warfare and how to assess these kinds of experiences. I hope it was helpful. But I’ve come to realize that the confusion between folk demonology and biblical teaching isn’t going away.

The topic of demonology is becoming more culturally significant as interest in the occult and paranormal continues to grow. “Spiritual” religions, such as Wicca, are some of the fastest growing in the Western world. In fact, the demand for exorcisms has risen so much that the Roman Catholic Diocese of Lugano appointed an official exorcist in 2025. We must address renewed interest with renewed discernment.

In Satan Cast Out: A Study in Biblical Demonology, a 1975 book by the late Frederick Leahy, formerly principal of the Reformed Theological College in Belfast, he tackles two common problems in Christian demonology. First, he pushes back on the tendency to use pagan beliefs about spiritual beings to guide the interpretation of the Bible. Second, he resists attempts to frame the way Christians think about demonology through experience instead of Scripture. As interest in the supernatural grows, Leahy’s warnings seem timely and relevant.

Uniqueness of the Bible

Some popular books on angels, demons, and similar subjects delight in telling us what the biblical author must have thought in light of what other writers of his time period—well, at least of the ancient world—thought in their own religious contexts and in their own languages. The underlying notion is that the Hebrew prophets saw the world basically in the same way that the ancient near eastern world did. In contrast, Leahy notes, “The fact is that the Biblical doctrine of Satan and his demons is radically different from the views of gods and spirits prevailing in pagan cultures” (70).

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