Classical Islamic jurists generally did not differentiate between the law governing the initiation of war (jus ad bellum) and the laws governing the conduct of armed conflict (jus in bello). Their discussions predominantly revolved around the concept of jihad from a religious and moralistic perspective, which requires extensive effort from later scholars to derive specific legal principles. This approach poses significant analytical challenges, as jihad is ambiguous, often attributed positive meanings by Muslim scholars while sometimes being contextualized by Orientalists within practical priorities. Furthermore, separating the rules governing the use of force from the rules governing the conduct of warfare requires considerable effort, as classical arguments often refer to the broad, indivisible concept of jihad.
The Ambiguity and Forms of Jihad
Jihad, a controversial yet purely Islamic term, literally means “exerting maximum effort and striving for success.” It is considered a major religious duty for all Muslims but possesses multiple and sometimes contradictory connotations. It has been widely misunderstood and misinterpreted by non-Muslims and abused by extremist groups, intensifying controversy, particularly regarding Islam’s stance on violence.
To better understand jihad, four intertwined forms are traditionally recognized. The first involves an internal struggle (jihad al-nafs) required of every Muslim for self-control and spiritual perfection, helping to avoid sinful behavior. The second is the individual responsibility to prevent or correct misbehavior harmful to society. These first two forms primarily concern individual obligation. The third form is the collective duty of the Muslim community to engage in a Holy War, declared by public authority, against those deemed aggressors, enemies, or infidels. The fourth is the obligation to disseminate the message of Islam using all reasonable means and methods. The latter two forms are generally considered collective duties.
Given the ambiguity and the concept’s recent revival by militant groups, there is a recognized need to reconceptualize jihad within the field of legitimate use of force, rather than solely in terrorism discussions. Textual analysis of the Quran implies that the use of force is conditional, requiring Muslims to fight in the name of Allah and observe prescribed boundaries, suggesting an underlying foundation for Islamic warfare related to jus ad bellum (conditions for initiating war) and jus in bello (rules during battle).
Interpretations of Jihad and the Use of Force
Recent literature review reveals three main perspectives on the subject. The first, considered apologetic, argues that jihad is fundamentally nonviolent, encouraging violent response only if the faith is attacked or insulted. The second group, classicists or neo-classicists, posits a perpetual state of war between Muslims and infidels, dividing the world into two warring factions—a view widely held but deemed unrealistic. The third viewpoint holds that violent jihad is justified under certain conditions, such as when Muslims are attacked or in response to rebellions or terror. This approach raises the question of whether jihad is solely necessary for spreading Islam, despite historical precedents of peaceful coexistence and honoring contractual obligations between Muslims and non-Muslims.
Siyar: The Islamic Law of Nations
Islamic scholars developed a semi-autonomous field of study called siyar, which focuses on the legal aspects of interactions between the Islamic political authority and other entities, including the legal study of armed conflicts from an Islamic perspective. Siyar establishes the legal groundwork for political, diplomatic, and warfare engagements, defining obligations for Muslim followers. Imam A’zam Abu Hanifa is credited as the first jurist to systematize this study, which was later significantly expanded upon by his disciple, Muhammad b. Hassan al-Shaybani, in his seminal work, Siyar al-Kabir. Because Shaybani’s original text is lost, contemporary analysis relies heavily on Muhammad b. Ahmad al Sarakhsi’s commentary (Sharh al Siyar al Kabir or al-siyar), which is recognized as an authoritative text utilized by institutions like the Ottoman state for training military officers and guiding conduct in war.
Produced during a period of Islamic political and military dominance, al-siyar adopts a unilateral approach, focusing on the rules binding Muslim combatants rather than prescribing reciprocal rules for opponents. Siyar is wide-ranging, covering topics from the legitimacy and preparation of war to the conduct of warfare, emphasizing the law of aman (safety/safe-conduct) and, extensively, the laws concerning spoils of war (anfal). It also addresses peace-making, co-existence, peace treaties, and the status of non-Muslim residents (dhimmi, musta’min) and apostates (murtad). Due to its scope, recent scholarship often regards siyar as the Islamic law of nations.
The Divine and Political Authority in Warfare
In classical Islamic law, the use of force (or jihad) must be carried out in the name of God, seeking to please Allah, which serves as the religious basis for justification. The Quran lays out two preconditions for jihad: it must be initiated in Allah’s name, and certain boundaries must be observed. This framework of fighting “in the way of Allah” forms the theoretical justification for the unilateral use of force, although practical interpretations have allowed Muslims to conclude agreements with non-Muslims that impose mutual restrictions.
Notwithstanding the religious foundations, the actual decision-making and enforcement framework for the use of force rests with the emir (head of the Islamic society/state). Jurists provided the theoretical groundwork for the ruler’s extensive powers. Sarakhsi and others granted the head of state practically unlimited authority to declare or cease war and appoint commanders. Loyalty to the ruler is considered absolute, based on prophetic statements, and jurists legitimize the ruler’s broad powers through Quranic texts and Hadiths. Compliance with the ruler is only nullified if the command clearly contradicts Allah, or, more tangibly in military action, if obeying risks complete destruction, a condition requiring majority consensus.
Preconditions for the Initiation of Force
Classical Islamic law outlines preconditions for initiating war. If a polytheist tribe has never heard of Islam, they must be invited to convert before the conflict begins. The rationale is that they might otherwise believe they are being fought solely for plunder, whereas accepting Islam avoids the need for violence altogether. If they accept conversion, the use of force becomes illegal. This perspective implies that the ultimate justification for war is inviting individuals to Islam, promoting the extension of the Islamic legal and political order.
The second criterion is inviting combatants (specifically the monotheistic “People of the Book”) to pay the jizya tax, implying their surrender to Islamic dominion in exchange for protection. Apostates, idolaters, or pagans, however, can only avoid force by converting. There is significant ambivalence regarding whether the invitation to Islam is always necessary. When Islam gained broader public recognition, some jurists argued the invitation was redundant, assuming the opponents were already aware of the call. Sarakhsi supported the view that both possibilities exist. Traditional legal thought developed three main views: 1) Invitation is absolutely necessary; 2) Invitation is unnecessary, as the ruling was abrogated after the early stages of Islam; 3) A reconciling view where the invitation is necessary only for those unfamiliar with Islam, while those already informed (like the Byzantines) can be attacked without prior notice.
The Unilateral Nature of Jihad
Classical jurists debated whether jihad was primarily a defensive measure or an unconditioned obligation to initiate war. Evidence supporting both views exists in the primary sources. Some narrations suggest Muslims are only obliged to fight if attacked. However, Sarakhsi aligns with the mainstream classical view that Muslims have an obligation to unilaterally initiate war against polytheists. He resolves the contradiction by applying the theory of abrogation, arguing that the divine command for jihad evolved gradually. Initial stages emphasized peaceful preaching, followed by permission for defensive jihad. In the final stage, according to Sarakhsi, verses commanding fighting in the way of Allah eliminated reciprocity and established the absolute and unconditional unilateral use of force against non-Muslims, aimed at glorifying religion. Consequently, theoretically, Muslims cannot refuse to resort to unilateral force, nor can they accept an enemy’s offer of peace if they possess sufficient strength.
This framework of unilateral obligation applies to maintaining the Islamic sociopolitical order. The severe classical stance allowing the use of force against apostates is not merely about individual conversion but rather fighting against those who renounce the legal and political system established by Islam. The overarching justification for the use of force remains the Islamization of the interlocutor—meaning their individual adoption of Islam or their consent to the rule of the Islamic political will.
Spoils of War as a Secondary Justification
While classical jurisprudence generally does not consider the potential acquisition of spoils (anfal or booty) a legitimate justification for initiating warfare, al-siyar addresses the issue extensively, giving it a materialistic tone that sets it apart from more purely divine discussions of jihad. The ability to obtain spoils is treated as a secondary incentive for engagement. The head of state possesses broad powers to regulate and allocate spoils in advance to encourage fighters, reinforcing the economic aspect of early Islamic warfare, particularly in an environment with limited resources. One-fifth of the spoils was inviolably allocated to “Allah” (interpreted as the central political authority), and the remaining four-fifths were distributed to the army. The allocation applied broadly, ensuring that anyone contributing to the conflict—including dhimmis, women, and slaves—was entitled to a share, reflecting the motivational function of booty.
Defense and Prohibitions on the Use of Force
Sarakhsi, and other classical jurists as well, confirm that defense is legally and morally permissible, even strongly encouraged. The community has an obligation to respond to any harassment, such as the abduction of property or citizens (including dhimmis who are owed protection). This obligation requires pursuing the enemy even into their own homeland if necessary.
However, the use of force is prohibited in several situations:
- The Haram Region: The sanctity and inviolability of the haram (sacred) region, inherited from pre-Islamic customs, are maintained. Once a person enters this zone, they cannot be arrested or killed, even if they were deemed executable outside the region.
- Aman (Safe-Conduct): This institution, rooted in pre-Islamic traditions and integrated into Islamic law, represents a legally enforceable contract where a Muslim grants temporary safe-conduct to a non-Muslim, terminating the use of force against the recipient. Aman is seen as strategically pragmatic, removing combatants from the battlefield and ensuring military efficiency. The privilege of aman lasts up to one year and cannot be unilaterally revoked by the granter unless the recipient commits a crime or causes harm to Muslims. Those granted aman receive protection within the Islamic homeland, similar to dhimmis.
- Non-Aggression Treaties: Treaties prohibit the use of force, but this prohibition is not absolute. In classical Islamic law, treaties are viewed pragmatically rather than as a strict normative adherence to pacta sunt servanda. If Muslims are stronger, they should prioritize battle. If Muslims are weak, they can enter treaties, even if unfavorable, to preserve their strength until they become powerful enough to unilaterally break the peace (with advance notification, unless no aman was granted or the enemy manifestly breached the treaty).
In summary, the classical Islamic legal framework for the use of force, as exemplified by al-siyar, is unilateral and primarily justified by the divine mandate to establish and expand the Islamic political and social order. While jurists provided the theoretical guidelines and preconditions (such as the call to Islam and jizya), the practical decision-making authority for war remained exclusively with the ruler, who was granted extensive powers rooted in religious legitimacy. The detailed discussions of jihad, its unilateral application, the rules of aman, and the economic aspects of spoils reveal a hybrid system balancing religious obligations with the temporal priorities of the nascent Islamic political entity.
