If you were to stop and consider the devil’s appearance for a moment, you might imagine something frightening. He very well may show up in your mind’s eye complete with horns, hoofs, and pitchfork. Maybe you’d dream up something that looks like it came out of a horror movie. The last thing we’d probably expect is for the devil to clothe himself in a godly appearance. But this is exactly how St. Paul describes him in 2 Corinthians 11:13. He says Satan “disguises himself as an angel of light.”
This makes good sense. The devil is crafty (Genesis 3:1). He certainly will not risk scaring off potential victims by breathing fire out of his mouth! The evil one doesn’t show up with the overt appearance of evil. Rather, he does his very best to give the impression of godliness. Because of this, we need to remain vigilant against the devil’s attacks. It’s not always easy to discern his work. He loves to make sin look as beautiful as possible (Genesis 3:6).
There’s something of a corrective needed to the popular view of Satan today. He will try first of all to convince people to deny his existence. After all, there’s no need to be on guard against something that’s not real. In the words of French poet Charles Baudelaire, “The greatest trick the devil ever played was convincing the world that he did not exist.” But if he can’t manage that, the next best thing is to get us to look for a devil that doesn’t resemble him at all. In his preface to The Screwtape Letters, C.S. Lewis wrote:
“Devils are depicted with bats’ wings and good angels with birds’ wings, not because anyone holds that moral deterioration would be likely to turn feathers into membrane, but because most men like birds better than bats.”
We know the devil is the enemy, and the pictures we paint of him (literally and in our imaginations) often follow suit. If we are on guard against something that looks demonic, we are less likely to notice him if he comes disguised as an angel. Satan wants us to associate him with scary, demonic-looking things. In this way, we are so busy looking for a distortion, we risk missing the real thing.
Commenting on Satan’s angelic disguises, Luther said,
“For in his ministers the devil does not want to be deformed and black but beautiful and white. To put on such an appearance he presents and adorns everything he says and does with the color of truth and with the name of God. This is the source of that familiar German proverb: “All misfortune begins in the name of God.”
If the devil seeks to present himself as an angel clad in white, it should come as no surprise that his servants often follow suit. Our Lord describes false teachers as “wolves in sheep’s clothing,” (Matthew 7:15). Like Satan, false Christianity seeks to make itself as attractive as possible. False Christianity, which is permissive and encourages indulgence, is much more attractive than true Christianity, with its call to repent, self-denial, bearing of the cross, and suffering for the sake of the Gospel. False Christianity is tolerant, inclusive, and popular. To disguise itself, it dresses up in sheep’s clothing. It will talk about believing the Bible, and probably put a good deal of emphasis on grace—so much so that you can do anything you want. To the question, “Shall we continue in sin that grace may abound?” (Romans 6:1), false Christianity asserts, “Amen, this is most certainly true!”
True Christianity, on the other hand, is not attractive to the sinful flesh. The righteous suffer in this life while the wicked prosper (see, for example, Psalm 6:2, 13:1—2, 35:17, 74:10, 82:2, 90:13, 94:3, 119:84). In Luther’s day, as in our own, many faithful congregations and pastor struggle. Luther said,
“In addition, no one provides for the preservation of the Gospel, and no one now will take any care for the support of ministers and the construction of schools. For the construction and establishment of false forms of worship and superstition, by contrast, no price was too high; but everyone contributed generously… But nowadays an entire city thinks that it is too much to support one or two ministers of the Gospel.”
False teachers show up in sheep’s clothing; they disguise themselves so as to not appear threatening. There is often some truth to what they say, even if it is only half-true. They will emphasize whatever truth is found in their message so as to gain a hearing, because nobody would follow something that was obviously false. In the words of Luther,
“But in the spiritual area, where Satan emerges not black but white, in the guise of an angel or even of God Himself, there he puts himself forward with very sly pretense and amazing tricks. He peddles his deadly poison as the doctrine of grace, the Word of God, and the Gospel of Christ. This is why Paul calls the doctrine of the false apostles and ministers of Satan a “gospel,” saying, “to a different gospel,” (Gal 1:6).
For all the threats to the church today, the greatest threat to the church comes from within, from what might seem like minor theological technicalities. Any false teaching, no matter how small, perverts the whole of the Gospel. As St. Paul says, “A little leaven leavens the whole lump,” (1 Corinthians 5:6). In the book of Revelation, our Lord uses the image of a prostitute to depict false Christianity. Outwardly, she appears beautiful, adorned with things that attract. She is arrayed in purple and scarlet, adorned with gold and jewels and pearls, and has in her hands a beautiful golden chalice (Revelation 17:4). She uses these things to seduce, to entice us into her trap. When we finally get close enough to look into her chalice, at first it appears to be filled with a deep, red wine. But by the time we realize that what she has become drunk on is not wine, but the blood of the saints (Revelation 17:6), it’s already too late.
It is for this reason that St. Paul urges the Church to “watch out for those who cause divisions and create obstacles contrary to the doctrine you have been taught,” (Romans 16:17). No matter how godly someone may appear, even if St. Paul came back from the dead or an angel came down from heaven and preached to you, if their doctrine is contrary to the Gospel, “let him be accursed,” (Galatians 1:8).
So, how can we guard against the devil’s attacks? The devil has an unlimited number of disguises in his wardrobe. Neither should our desire to grow in God’s Word have any limit. Whether Satan shows up as an angel of light or darkness, the Gospel will always expose him for the liar and the murderer that he is (John 8:44). The pure Word of God will always chase him away (Matthew 4:11). As we sing in “A Mighty Fortress”, “One little word can fell him,” (LSB, 656, verse 3). And indeed, he’s judged, the deed is done. Our victory has been won! Thanks be to God, who gives us the victory through our Lord Jesus Christ (1 Corinthians 15:57)!
 Luther’s Works (AE). Lectures on Galatians (1535). Chapters 1—4. St. Louis: CPH, 1963 (50).
 Ibid., 105.
 Ibid., 49.