The Legal and Historical Evolution of Jewish Military Ethics

BY TZUR SHALIT

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“I must study Politicks and War that my sons may have liberty to study Mathematicks and Philosophy.” – John Adams (1)

The great societies of the past, categorized by their religions, produced distinguished approaches to dealing with their particular affairs relating to war, based on the zeitgeist of moral and ethical considerations of each particular society. The Christian tradition created the just war theory; it is built on the balance of the state’s moral duty to protect its citizens and the individual Christian’s moral duty to adhere to Christian teachings, particularly regarding the sanctity of each individual life, creating criteria under which war is justified. The Chinese tradition, though far more permissive than the Christian one, established a distinct bar for just war and military conduct, which nonetheless emphasized the morality and immorality of certain warfare. 

In great contrast to these heritages, the Jewish tradition is unique because it lacks a practical application for the ethics of war, as Jews in the diaspora did not have a military, generals, or a kingdom. Yet, despite the nonexistence of Jewish warfare from the time of Josephus until the early twentieth century, one cannot overstate how vital the Jewish tradition of the ethics of war has been to the evolution of contemporary military ethics. In the last century, Jews have had the most revolutionary legal evolution from theory to practice of any nation in the previous two millennia through the establishment of the Jewish state. 

Understanding the evolution of Jewish military law since Israel’s founding requires pondering the evolution of military law as a whole. While there is no definitive way to know when the legal organization of conflict began, since the time of the Romans, (2) there have been recorded traditions of what conditions are allowed in armed conflict. In his book War and Our World, military historian John Keegan writes that “the ethical code of restraint in military interactions has rarely been wholly absent from practical war.” (3) As Greek philosopher Celsus put it, the law is the art of the good and the equal,(4) and it is the organizational structure of successful international relations. Armed conflict has always been a difficulty in these relations, especially between the city states that ruled the ancient world. As much as morality and goodness have affected the evolution of the law of war, economic factors have also led to the evolution of the law of military conduct and ensuring strict adherence to this law.

All international treaties, agreements between nations to uphold certain standards, are based on one legal principle, pacta sunt servanda, (5) Latin for “agreements must be kept.” This is in the background of all international law; by extension, the law of war, as the most essential branch of international law, is indebted to this principle. Within this framework, the law of war is partitioned into two fields. The rules and laws governing the initial resort to armed conflict, known as jus ad bellum, and the rules and laws governing the conduct of armed conflict, jus in bello. (6) These frameworks categorize the law of war. They have been developed throughout history to regulate the human practice of war and minimize the moral and economic pain it brings. 

The fact that Jews did not deal with war for a considerable amount of their history did not preclude the Rabbis from discussing its ethics. War is a theme present in the Torah; accordingly, it is discussed, theorized, and evaluated in the Jewish tradition. In this tradition, there has been a discouragement away from Jews being active in warfare. The most apparent example is that King David was not allowed to build the Temple because of his active involvement in war. Still, there is a constant rich tradition of Jewish theory regarding the laws of war and the ethical implications of warfare. 

It is, however, essential to note that the ancient Rabbinic systemization of the laws of war is different from the contemporary international legal standard, as the ethics of going to war are now legislated in a far stricter manner. In his recent book, Ethics of Our Fighters: A Jewish View on War and Morality, Rabbi Shlomo Brody expands on this, saying, “a dominant strand within Talmudic law, followed by Maimonides and others, distinguished between two types of wars: obligatory, including wars of self-defense and the destruction of the Canaanite and Amalek nations, as opposed to discretionary wars, such as expansionist warfare.” (7) This distinction between two types of wars, obligatory and discretionary, fits into the jus ad bellum structure of military law. 

In the Jewish tradition, the standards of conduct and eligibility of soldiers varied depending on the war’s classification. In an obligatory war, the biblical king could exercise unilateral authority because the rationale was to protect as many people as possible. For this reason, in an obligatory war, everyone capable was required to fight or contribute to the war effort in order to protect the collective. In a discretionary war, this was not the case. The king had to receive approval from the judicial and legislative assembly, the Sanhedrin, before he was able to launch the war. Soldiers could also choose to opt out of this type of war, making the king’s maximum military output less effective but allowing each individual to evaluate the war’s morality. Another major factor of discretionary war is that territory captured by the king without the approval of the Sanhedrin is not considered to be part of the nation. The Sanhedrin is given full authority to determine both jus ad bellum considerations by understanding the moral issue in front of them and jus in bello factors by appraising moral conduct in war.

The Torah exemplifies the issues of potential immorality that can arise without a code of military law. While King David was engaged in a discretionary war, (8) he entered an affair with Bathsheba, a married woman. He abused his role as king by sending her husband to the front line and ordering his troops to retreat, leaving him dead. The Torah uses this as an example of the absolutist militants that the Jews are warned not to become as well as the moral pitfalls of unchecked military power. This is the motivation for separating powers away from the discretion of the king. Such was the status quo for David and the kings that followed. But, after the fall of the Davidic dynasty, the Jews became integrated with the broader world for the first time, in exile and without an army. 

Jews in exile of any particular nation have always endeavored to adhere to scrutiny through two forms of law: halakha, Jewish religious law, and the local statutes of the polity in which they reside. This was true for the majority of legal issues, but some things, like the shmitah cycle, resting the land every seventh year, had no legal application outside of the Land of Israel. The same phenomenon is true of most biblical agricultural laws, laws related to the affairs of the legislative and judicial power, and laws relating to the execution of the duties of a civil government, most notable among which is the institution of warfare. Diaspora Jews had little application of a legal military code without a state. They also referred to these laws in religious doctrine as not applicable outside of the Land of Israel. There was no practical application for these laws in the Diaspora.

Since the time of the Maccabees, the Jewish people had not been a fighting nation. In the early nineteenth century, the Zionist movement began to change that. This Zionist perspective is captured in the poetry of the time. After a horrifying pogrom in Kishinev, Hayim Nahman Bialik, a powerful Zionist poet, wrote “In the City of Slaughter,” a harsh criticism of the local Jewish men who were “Crushed in their shame, they saw it all; they did not stir or move…Perhaps, perhaps, each watcher had it in his heart to pray: a miracle, O Lord—and spare my skin this day!” (9)

Not all Zionists shared the understanding that religiosity is a shameful practice; the notable Orthodox Rabbi and early adopter of Zionism, Rabbi Aaron Samuel Tamares, argued that Jews “strive for real manhood…the study of Torah.” (10) Yet, under the British Mandate, the image of the fighting Jew was instituted in the psyche of the Yishuv, the pre-independent state of Israel. Zionist leaders like Vladimir Jabotinsky, Rav Abraham Isaac Kook, Eliyahu Golomb, and Berl Katznelson, among many others, created the intellectual and physical, including military, movement required for the Jewish state to come into being. 

In 1948, after years of facing Arab riots, murder, and violence, the Jewish state was established. As a matter of survival, nations need laws that regulate battle, warfare, and other morally challenging situations. The Jewish people had to become a country, and suddenly, the nascent nation had to establish a code of military behavior. 

With the establishment of the state of Israel, the Israel Defense Forces (IDF) was created. The various Jewish defense groups active in Mandatory Palestine were consolidated into one by Israel’s first Prime Minister, David Ben-Gurion. This consolidation also included legal factors. There were varying regulations of military operations within the initial defense groups, primarily the Haganah and Irgun, but the new IDF could not have this lack of standardization. As part of its mission to protect the existence, territory, and sovereignty of the state of Israel, the IDF created a code, Ruach Tzahal—the ethical principles of the IDF—with four fundamental considerations: the military tradition of the IDF and its heritage; the principles of the state of Israel, its laws and institutions; Rabbinic and Jewish law throughout the ages; and the universal moral values and dignity of human life. (11)

To be a Jew in modernity means that one must have a particular awareness of the law, both Jewish and societal, when, inevitably, interacting with the outside world. Jews must be aware of our history and of our moral potential. The original Ruach Tzahal can inspire contemporary Jews to consider the entire framework of the legal code, both religious and secular, when dealing with issues related to the law of armed conflict. The modern Jew must be aware of his power, of his right to self-defense and self-determination. Still, he must also maintain a hesitancy to arms and maximization of Torah study. For war is not an aspect of Jewish identity; it is a consequence of living in the world as it is, and for Israel today, the neighborhood in which it is located. 

May we see the day that Isaiah’s prophecy is fulfilled and that “nation will not lift up sword against nation; neither shall they learn war anymore.” (12) Then, we will be able to fulfill Adam’s vision: “My sons ought to study Mathematicks and Philosophy, Geography, natural History, Naval Architecture, navigation, Commerce and Agriculture, in order to give their Children a right to study Painting, Poetry, Musick, Architecture, Statuary, Tapestry and Porcelain.” (13)

Notes and works cited:

[1] John Adams to his wife, Abigail, on the 12th of May, 1780.

[2] For more information on this, see page 2 of The Law Of Armed Conflict: International Humanitarian Law in War The Third Edition by Professor Gary D. Solis, Cambridge University Press, 2022.

[3] See page 26 of War and Our World by John Keegan, Vintage Books, 2001.

[4] A reference to Celsus’s famous saying, “lus est ars boni et aequi – the law is the art of the good and the equal.”

[5] See the UN Vienna Convention on the Law of Treaties (1967) Article 26.

[6] See page 17 of The Law Of Armed Conflict: International Humanitarian Law in War The Third Edition by Professor Gary D. Solis, Cambridge University Press, 2022.

[7] See page 168 of Ethics of our Fighters: a Jewish View on War and Morality by R. Dr. Shlomo M. Brody, Maggid Books, 2024.

[8] Ibid. page 170. See more information about this war and the evolution of modern international law in this section.

[9] Ibid. page 13, citing Hayim Nachman Bialik’s In the City of Slaughter.

[10] Ibid. citing R. Aaron Samuel Tamares.

[11] In 2022 this code was changed to include Stateliness. See the update Ruach Tzahal.

[12] Yeshayahu – Isaiah 2:4.

[13] See the first note. This is the continuation of that quote, Adam’s hope for the future.