This article about deception and perfidy in the Christian just war tradition and Islam originally appeared in the Winter 2018 issue of Providence‘s print edition. To read the original in a PDF format, click here. To receive future issues as soon as they are published, subscribe for only $28 a year.

Rahab stuck her neck out to help the two spies Joshua dispatched to reconnoiter Jericho, and she’s duly honored later in Hebrews 11’s “Faith Hall of Fame.” Though, as revealed in Joshua 2, she lied to city authorities to protect the undercover Israelites, these courageous men of God didn’t rebuke her for speaking falsehood. Rather, they cherished the care and intel she provided them and made sure she was safe when the city was sacked. So, we might be inclined to excuse her for telling the city cops, “They went thataway!” when she well knew the Hebrews were hiding on the premises. But Augustine would have none of that. He maintained she was wrong to have lied, though she may well have done so only because, as a pagan, she wasn’t aware of the Mosaic Law. She was rewarded for “benevolence” rather than “deceit,” for “benignity of mind, not the iniquity of lying.”[1]

Augustine & Aquinas

For Augustine, the prohibition against lying was absolute. In his essays on the subject, he appealed to the Decalogue’s proscription of “false witness,” to Jesus’ directive that we stick fastidiously to “yea” and “nay,” and to Paul’s insistence that the “new man” should “put away lying.” Furthermore, Augustine found no scriptural reason to think the condemnation of mendacity had been abrogated or qualified.[2]

In Summa Theologica, Thomas Aquinas took up the question of truth-telling in his remarks on ambushes, which some count as illicit deception, since those who hide say, in effect, “Nobody dangerous is awaiting you here.” Turns out, both he and Augustine, whom he cited in this connection, made allowance for this practice. After all, we don’t have an obligation to reveal everything we know. Indeed, God Himself told Joshua to “lay ambushes for the city of Hai” (Josh. 8:2), and Jesus counseled his followers to conceal certain things from derisive unbelievers—“Give not that which is holy to dogs” (Matt. 7:6). But Thomas drew the line against telling someone something false or the breaking of promises. These are “always unlawful.”[3]

It strikes me that this is slicing things a bit thin. Insisting that the distinction between “withholding or concealing” and “presenting or telling” marks the beginning of a lie could lead to absurdities: such as insisting there’s a morally relevant difference between putting on camouflage—with streaks of grease paint on your face and grass in your helmet band—and 1) intending to withhold knowledge of your presence, and 2) intending to present yourself as part of the vegetation. In both cases, the intention is to give the enemy the wrong impression.

The Principle Behind the Rule

Popular images of the Decalogue tablets sometimes render the sixth commandment as “do not kill” and the ninth commandment as “do not lie.” Both renderings are misleading. In the former instance, it should read, “do not murder.” Among other reasons, we know this because in the very next chapter, Exodus 21, God prescribed the death penalty for certain offenders. As for the latter commandment, the ninth, the sense of the actual wording, “do not bear false witness,” and the modifier, “against thy neighbor,” is often downplayed, even when accurately quoted. In trying to understand either commandment, we stumble when we fix on the rule with no sense of context or the underlying principle, namely justice.

Killing is morally evil when it takes an innocent life intentionally. Bearing false witness is a forensic concept centered on slander and libel in the court of public opinion and perjury against an innocent party in a court of law. Both turn on the issue of willful harm to those who don’t deserve it.

What constitutes harm? I’d suggest it boils down to loss of freedom. If a madman kidnaps me and locks me in a basement, he’s taken away my freedom to move about the world according to my values and plans. If the county sheriff locks me in a basement jail cell because I drove drunk into a busy crosswalk, he deprives me of the same opportunities—he harms me in the same way—but justly so. It’s not the locking in a basement per se that’s wrong, but the undeserved confinement therein. Some harms are warranted.

So, what shall we say of lying or deception? It too is a form of confining or shackling someone—in this case with a false narrative—to a condition limiting the person’s ability to act judiciously. If you tell me that you have a medical degree when you don’t, you not only steal something (credit for having professional credentials), but you also put me in a dangerous position of trust, hedging me about with dangerously false expectations.

The harm of a lie is perfectly fitting for catching a bank robber seeking confidential treatment for the broken leg he suffered when jumping from the teller’s counter. If we can trick him by offering, on the dark web, clandestine medical services for felons and entice him to visit our “clinic” (where he’ll be nabbed), we’ve done something proper. Our phony statements “put him in a box” and deprived him of the freedom to make a well-informed choice, but that’s a good thing, along with another good thing—putting him in a literal box in the hoosegow.

The issue is not whether I concealed as opposed to signaled a state of affairs, but rather the nature of the one to whom the concealing or signaling is aimed. There are no absolute moral rules against imprisonments and falsehoods, but there are rules against unjustly-imposed imprisonments and falsehoods.

David Gushee makes the point in Kingdom Ethics, where he draws on the example and writings of Dietrich Bonhoeffer vis-à-vis the Nazis. He argues that “you have to ask in what way a person is entitled to demand truth speech from others.” He posits “implicit covenants” for candor, the sort not suitable with the SS, the Nazi Party’s elite paramilitary organization.[4]

Room for Ruses & Feints

Just war tradition has followed this thinking, permitting great leeway for deception. Examples abound:

  • Confederate General Adam Johnson, with a force of only 12 men, compelled 2,000 Indiana militiamen to evacuate Newburgh, Indiana. He simply mounted stovepipes on his wagons, creating the impression of artillery.[5]
  • Another Confederate general, Nathan Bedford Forrest, sent mounted troops through dry cornfields “shouting orders to non-existent units.” A single horse and rider could sound like ten.[6]
  • In southeast England, World War II Allied forces employed “wetbobs” (fake landing craft assault ships) and “bigbobs” (fake landing craft tank ships) with oil seepage, wash-laden clotheslines, etc., to deceive the Germans about the location of the impending invasion of the continent.[7]
  • In 1943 the British took the corpse of an indigent, Glyndwr Michael—who died by suicide—dressed and outfitted him as a military courier (“Acting Major William Martin”), and cast him ashore on the Spanish coast, where Germans accessed his bogus message and acted accordingly, shifting troops to Greece to meet an invasion which was actually set for Sicily.[8]
  • During one of the kamikaze attacks on the Fifth Fleet as it lay off Okinawa in the Spring of 1945, naval historian Samuel Eliot Morison “observed two aircraft apparently locked in a deadly dog fight. Suddenly, they broke off the fight, and both dived on American warships. The dog fight had been a clever, and successful, ruse to keep American fighters from interfering with the two kamikazes, and to keep ships’ antiaircraft gunners from taking the risk of shooting down a ‘friendly’ airplane.”[9]

No Room for Perfidy

There are, however, limits to the deception morally allowable in war. Not just anything goes. There are cases where I must trust you, and you must trust that I trust you—violations of which are considered acts of perfidy or treachery.

In covering the suicide-bomb murder of four American soldiers by an Iraqi army officer in 2003, The Telegraph explained the crime:

“The feigning of civilian, non-combatant status is one of the acts of perfidy specifically prohibited by the first protocol to the Geneva Conventions, adopted in 1977. Other examples of perfidy are misusing a flag of surrender and pretending to be wounded.”

Although this protocol has not been ratified by the United States—or, indeed, Iraq—perfidy is a generally accepted principle of international law. Article 37 of the first protocol defines it in terms of betraying a confidence. Troops might reasonably drop their guard when approached by civilians or men with white flags; it is therefore perfidious to misuse the status of a non-combatant.[10]

Contempt for perfidy is cut from the broader just war cloth. It honors the jus ad bellum principle of “right intent” (i.e., a just peace) in that flags of truce are peace-seeking instruments. It honors the jus in bello principle of “distinction,” by which non-combatants are not targeted—combatants posing as non-combatants could tempt good troops to abandon that scruple. It also honors the concerns of jus post bellum, for acts of treachery during war can prompt punitive, petulant, and provocative “overkill” by the victor in settling things at the end.

The perfidy taboo enjoys a long history. For instance, in The Book of Deeds of Arms and Chivalry, Christine de Pizan (1364-1431) argues that the Bible allows “ruse, wiles, or tricks” in war, but there are “tricks that are unacceptable and forbidden” in all cases.

“For instance, were I to assure somebody that if he came to see me in an allotted place, I would be there to speak with him, and he came according to my assurance, and I surprised him there by some trick to harm him or kill or capture him, such an act would be right evil treason.”[11]

In the seventeenth century, Samuel von Pufendorf seconded this sentiment, saying in On the Duty of Man and Citizen that one has the “right to use fraud and deceit against an enemy, provided one does not violate one’s pledge of faith. Hence, one may deceive an enemy by false statements or fictitious stories, but never by promises or agreements.[12]

The notion has been echoed repeatedly, as in the American Civil War, when General Orders, No. 100, at article 118, directed, “It is justly considered an act of bad faith, of infamy or fiendishness, to deceive the enemy by flags of protection,” for, as it said in article 114, the flag of truce has a “sacred” character, and its abuse is “an especially heinous offense.”[13]

Despite these scruples, the practice continues:

“One tactic from Palestine—the suicide vest—is relatively new to both Iraq and Afghanistan. Right before 9/11, bombers posing as journalists [“feigning civilian status”] killed Northern Alliance leader Massoud.

At the start of the U.S. Assault on Fallujah in November of 2004, one group of insurgents waved a white flag as if to surrender: As soon as U.S. forces exposed themselves, they came under heavy, well-directed machinegun fire.”[14]

Alas, the aforementioned Confederate Nathan Bedford Forrest also flirted with this sin when he sent fake deserters into the Union camps to paint false pictures and size up the enemy. Once released to go home, they scurried back to Forrest to report and resume their belligerency.[15] The moral problem lay in their non-combatant drama. (Incidentally, this is an old trick, one performed by the Hittites on Ramses II in 1288 at the battle of Kadesh.[16])

Dar al-Harb, Jihad, & Taqiyah

Though we cannot do the topic justice, I think it’s instructive to take a brief look at Islam for purposes of contrast. Neither their literature nor their track record mirrors the scruples common in the West. But first, let’s visit a quote from Sissela Bok’s book Lying, one that reflects the tension common in Judeo-Christian cultures:

“[A] special case might be made for deception in lawful, declared hostilities, as against tax-evaders or counterfeiters, or between openly warring parties. Such open declarations lessen the probability of error and of purely personal spite, so long as they are open to questioning and requests for accountability.”[17]

Straightforward enough, but for Islam, there are two hitches:

  • If zealous, the Muslim is continually at war (jihad) with the unbeliever, the infidel who refuses to submit to Allah; for him, the world is divided between Dar al-Islam (Domain of Islam)—the territory where Islam rules—and Dar al-Harb (Domain of War)—the territory under the control of unbelievers, in active or potential conflict with Islam’s domain.[18]
  • Within this perpetual state of war, there is no firm prohibition on lying; rather, taqiyah (strategic deception) is sanctioned, not only in the cause of military victory but also for purposes of securing and extending the sway of Muslim preachments and public policies.  [Among the sources for this doctrine are the Qur’an 2:225 and 16:106, which allow Muslims to protect themselves by denying the faith, so long as they don’t really mean their recantations; and the writings of eminent Muslim authority Al-Ghazali (d. 1111), who held that Muhammad said it was acceptable to lie in three circumstances: for reconciliation among people; in war; and amongst spouses, to keep peace in the family.][19]

If you pair “lying in war is fine” with “our dealings with unbelievers are perpetually a matter of war” (and so, they don’t deserve the truth), you open the door for advantageous deception in virtually all of life. And the nice distinction Bok advances falls by the wayside:

“Whenever it is right to resist an assault or a threat by force, it must then be allowable to do so by guile. But the criteria for who is to count as presenting such a threat must be publicly justifiable. In this way, deceiving a kidnapper can be distinguished from deceiving adversaries in business.”[20]

None of this is to suggest that most Muslims assume this aggressive, deceitful posture, any more than to suggest that most who attend Christian churches are faithful in stewardship, evangelism, and other hallmarks of discipleship. It does say that the warrant to deceive is present for Muslims who want to cut moral corners on integrity and mutuality.

But are there doctrinal limits to this deception? Arguably, no. In Understanding Jihad, David Cook cites Muhammed Khyar Haykal, whose three-volume treatment of the subject touches on little-discussed issues such as the role of women in jihad, the use of weapons of mass destruction, and the matter of surrender.[21] His take: “What are the outer limits of the trickery and lying that the shari’a permits under these [war] circumstances? In general, the answer to this last question is that the limits are removed according to the exigency of the situation.”[22]

To be sure, some Muslim writers insist that Islam honors just war principles, and of course some Muslim scholars and schools fashion strictures of one sort or another. They work from a verse in the Qur’an, 2:190: “Fight in the way of Allah those who fight you but do not transgress. Indeed, Allah does not like transgressors.” A transgressor of course is, by definition, one you fault. But how might you identify one? Abu Bakr, for one, drew the line against mutilating dead bodies, killing children, and destroying trees, among other things.[23] But interpreters of the Qur’an and Hadith are, in effect, taking an elaborate Rorschach test, seeing what they’re inclined to see. Too often the Qur’an is treated as little more than a buffet line of cherries from which one may pick some and ignore others to fill his ideological plate. Thus, to claim that the treacherous Muslims in Fallujah were not “real Muslims” is more stipulative than descriptive.

Be that as it may, there should be no doubt that, had Jerichite Rahab not only lied to fellow Jerichites but lured them into her home with poison-laced cake and watched in satisfaction as they fell to the floor in agony, our Judeo-Christian alarm bells would sound. Deception is one thing. Treachery is another.


Mark Coppenger is a professor of Christian philosophy and ethics at The Southern Baptist Theological Seminary, managing editor of the online Kairos Journal (providing articles for the Nelson NKJV Unapologetic Study Bible), and author of Moral Apologetics (B&H). He is a retired infantry officer.


[1] Augustine of Hippo, “To Consentius: Against Lying,” A Select Library of the Nicene and Post-Nicene Fathers of the Christian Church, ed. Philip Schaff, vol. 2 (Buffalo: The Christian Literature Company, 1887), 495-497.

[2] Robert Dodaro, “Lying and War,” under “Ethics” in Allan D. Fitzgerald, Augustine Through the Ages: An Encyclopedia (Grand Rapids: Eerdmans, 1999), 328-329.

[3] Thomas Aquinas, “Question XL: Of War,” Summa Theologica, Great Books of the Western World,  ed. Robert Maynard Hutchins, vol. 20 (Chicago: Encyclopedia Britannica, 1952), 580-581.

[4] David P. Gushee and Glen H. Stassen, Kingdom Ethics: Following Jesus in Contemporary Context, 2nd ed. (Grand Rapids: Eerdmans, 2003, 2016), 303.

[5] Samuel W. Mitcham, Jr., Bust Hell Wide Open: The Life of Nathan Bedford Forrest (Washington, DC: Regnery, 2016), 69.

[6] Mitcham, Jr., 77-78.

[7] Mary Katherine Barbier, D-Day Deception: Operation Fortitude and the Normandy Invasion (Mechanicsburg, PA: Stackpole, 2007), 28, 77.

[8] Ben Macintyre, Operation Mincemeat: How a Dead Man and a Bizarre Plan Fooled the Nazis and Assured an Allied Victory (New York: Harmony Books, 2010), 120.

[9] James F. Dunnigan and Albert A. Nofi, Victory and Deceit: Dirty Tricks at War (New York: William Morrow, 1995), 164.

[10] Joshua Rozenberg, “The perils of perfidy in wartime,” The Telegraph, April 3, 2003,

[11] Quoted in Gregory M. Reichberg, Henrik Syse, and Endre Begby, The Ethics of War: Class and Contemporary Readings (Oxford: Blackwell, 2006), 219-220.

[12] Quoting from Reichberg, Syse, and Begby, 458.

[13] Cited in John Fabian Witt, Lincoln’s Code: The Laws of War in American History (New York: Free Press, 2012), 389.

[14] H. John Poole, Militant Tricks: Battlefield Ruses of the Islamic Insurgent (Emerald Isle, NC: Posteriety Press, 2005), 212, 223.

[15] Mitcham, 77.

[16] Michael Dewar, The Art of Deception in Warfare (Newton Abbot, UK: David & Charles, 1989), 26.

[17] Sissela Bok, Lying: Moral Choice in Public and Private Life (New York: Vintage/Random House, 1978), 144.

[18] “Top 35 Islamic Terms,” Kairos Journal,

[19] Abdullah Al Araby, “Lying in Islam,” Islam Review,

[20] Bok, 144.

[21] David Cook, Understanding Jihad (Berkeley: University of California Press, 2015), 124. The Haykal book is Jihad and Fighting according to the Shar`i Policy (al-Jihad wa-l-Qital fi al-siyasa al-shara`iyya) (Beirut: Dar al-Barayiq, 1993).

[22] Cook, 126

[23] Shiraz Maher, Salafi-Jihadism: The History of an Idea (Oxford: Oxford, 2016), 46.