These legal guidelines concerning jihad are taken from the commentaries of 'Umar Barakat (c.1890) on the 14th century writings of Ahmad ibn Naqib al-Misri, in the Shafi'i school, one of the four major schools of Islamic jurisprudence. Within the range of Islamic thought, Shafi'is have a rationalistic interpretation of shari'a, unlike the extremism of some of the fundamentalists. Yet I think you'll find these plain-spoken accounts eye-opening, if you haven't seen them before.
The Muslim schools are identical in about three-fourths of their legal conclusions, and most of the differences are methodological. I am not aware of serious variances over the issues of jihad presented here; the one I can see clearly is outlined in the quoted text.
Though these texts are in some cases ancient, they are still in print, taught and learned and revered in the Islamic world. They are the basis of proper behavior for observant Muslims.
Jihad means to war against non-Muslims, and is etymologically derived from the word mujahada, signifying warfare to establish the religion. And it is the lesser jihad. As for the greater jihad, it is spiritual warfare against the lower self (nafs), which is why the Prophet (Allah bless him and give him peace) said as he was returning from jihad,
"We have returned from the lesser jihad to the greater jihad."
The scriptural basis for jihad, prior to scholarly consensus is such Koranic verses as:
(1) "Fighting is prescribed for you" [Koran 2:216];
(2) "Slay them wherever you find them" [Koran 4:89];
(3) "Fight the idolaters utterly" [Koran 9:36];
and such hadiths as the one related by Bukhari and Muslim that the Prophet (Allah bless him and give him peace) said:
"I have been commanded to fight people until they testify there is no god but Allah and that Muhammad is the Messenger of Allah, and perform the prayer, and pay zakat. If they say it, they have saved their blood and possessions from me, except for the rights of Islam over them. And their final reckoning is with Allah";
and the hadith reported by Muslim,
"To go forth in the morning or evening to fight in the path of Allah is better than the whole world and everything in it."
[Jihad is obligatory upon Muslims, but there are two kinds of obligations in Islam, the personal and the communal. A personal obligation is required "from each and every morally responsible person." A communal obligation is required "from the collectivity of those morally responsible." If no one from the community undertakes it, then all are guilty of a serious sin. If one or some undertake it, then the obligation is fulfilled.
In normal situations, for Muslims at home in their own country, jihad is a communal obligation. But "when non-Muslims invade a Muslim country or near to one, ... jihad is personally obligatory upon the inhabitants of that country, who must repel the non-Muslims with whatever they can."]
- "It is offensive to conduct a military expedition against hostile non-Muslims without the caliph's permission, though if there is no caliph, no permission is required."
- "Muslims may not seek help from non-Muslim allies unless the Muslims are considerably outnumbered and the allies are of goodwill towards the Muslims."
- "The caliph makes war upon Jews, Christians, and Zoroastrians, provided he has first invited them to enter Islam in faith and practice, and if they will not, then invited them to enter the social order of Islam by paying the non-Muslim poll tax -- which is the significance of their paying it, not the money itself -- while remaining in their ancestral religions. And the war continues until they become Muslim or else pay the non-Muslim poll tax, in accordance with the word of Allah Most High,
'Fight those who do not believe in Allah and the Last Day and who forbid not what Allah and His messenger have forbidden -- who do not practice the religion of truth, being of those who have been given the Book -- until they pay the poll tax out of hand and are humbled.' [Koran 9:29]"
- "The caliph fights all other peoples until they become Muslims, because they are not a people with a Book, nor honored as such, and are not permitted to settle with paying the poll tax, though according to the Hanafi school, peoples of all other religions, even idol worshippers, are permitted to live under the protection of the Islamic state if they either become Muslims or agree to pay the poll tax, the sole exceptions to which are apostates from Islam and idol worshippers who are Arabs, neither of whom has any choice but becoming Muslim [al-Hidaya sharh Bidaya al-mubtadi']."
- "It is not permissible in jihad to kill women or children unless they are fighting against the Muslims. Nor is it permissible to kill animals, unless they are being ridden into battle against the Muslims, or if killing them will help defeat the enemy. It is permissible to kill old men, meaning someone more than forty years of age, and monks. ... It is permissible in jihad to cut down the enemy's trees and destroy their buildings."
- "When a child or a woman is taken, they become slaves by the fact of capture, and the woman's previous marriage is immediately annulled."
- "When an adult male is taken captive, the caliph considers the interests of Islam and the Muslims and decides between the prisoner's death, slavery, release without paying anything, or ransoming himself in exchange for money or for a Muslim captive held by the enemy."
- "In Sacred Law truce means a peace treaty with those hostile to Islam, involving a cessation of fighting for a specified period, whether for payment or something else." A truce is "a matter of the gravest consequence because it entails the nonperformance of jihad." "There must be some interest served in making a truce other than mere preservation of the status quo."