It’s simple: Jihad is required by Sharia, and worldwide Sharia is the goal of Jihad. They are joined at the hip. Now I’ll back this up with solid evidence.
There are four major schools of Sunni Sharia law. About 85% of Muslims are Sunni, and it is generally suggested that they pick one of the four major schools to follow. Although it may seem that the fact there are four schools means Islamic law is not a monolith, in reality, they are unanimous on 75% of the issues. When there is disagreement, three of the four schools are often in agreement (according to the introduction to Reliance of the Traveller: A Classic Manual of Islamic Sacred Law, 1994 Revised Edition, certified by the prestigious al-Azhar University of Cairo).
This is important because of the Islamic doctrine of “ijma”, or consensus. According to this doctrine, any time the Muslim world reaches a consensus, it cannot be wrong. You might think that since there are over a billion Muslims worldwide, a consensus would be impossible; however, Muslim authorities have found a way around this in how they define “consensus”. First, only the opinions of the highest religious authorities counts. Second, if at any time there is a consensus among the highest authorities, after that the dissenters can be ruled “heretics” so their opinions don’t count, either. It’s really very clever.
The consequences of this doctrine are far-reaching and tragic. Many centuries ago, there were highly regarded Muslim legal scholars called mujtahedin. These were rare individuals; in order to be considered a mujtahedin, a person would have to fulfill stringent qualifications. Only a mujtahedin of the first class had the authority to write new law based on the Quran and other foundational religious texts, without consulting the work of earlier mujtahedin. The last mujtahedin of the first class was Ahmed ibn Hanbal, who died in 855 A.D. The process of independently creating new law is called ijtihad.
According to Islamic scholar Cyril Glasse, about 900 years ago, it was clear that there was consensus on all the major religious issues. Because of the doctrine of ijma, this consensus meant their decisions were infallible, and therefore it was no longer permissible to write new law. The gates of ijtihad were closed in Sunni Islam. (According to some experts, this occurred at an even earlier date.) Today, Muslim clerics can issue fatwas applying existing law to events, but they are not qualified to disregard the mujtehedin and go straight to the Quran and Sunnah.
So, what does Sharia say about Jihad? Let’s examine the legal writings of each of the four major schools of Sharia. Thanks to Robert Spencer for these quotes:
Maliki School, jurist Ibn Abi Zayd al-Qayrawani (d. 996):
“Jihad is a precept of Divine institution. Its performance by certain individuals may dispense others from it. We Malikis maintain that it is preferable not to begin hostilities with the enemy before having invited the latter to embrace the religion of Allah except where the enemy attacks first. They have the alternative of either converting to Islam or paying the poll tax (jizya), short of which war will be declared against them.”
Hanbali School, jurist Ibn Taymiyya (d. 1328), popular with modern terrorists:
“Since lawful warfare is essentially jihad and since its aim is that the religion is God’s entirely and God’s word is uppermost, therefore according to all Muslims, those who stand in the way of this aim must be fought. As for those who cannot offer resistance or cannot fight, such as women, children, monks, old people, the blind, handicapped and their likes, they shall not be killed unless they actually fight with words (e.g. by propaganda) and acts (e.g. by spying or otherwise assisting in the warfare).”
Hanafi School, Hedaya, classic manual of Hanafi laws, 12th century:
“It is not lawful to make war upon any people who have never before been called to the faith, without previously requiring them to embrace it, because the Prophet so instructed his commanders, directing them to call the infidels to the faith, and also because the people will hence perceive that they are attacked for the sake of religion, and not for the sake of taking their property, or making slaves of their children, and on this consideration it is possible that they may be induced to agree to the call, in order to save themselves from the troubles of war… If the infidels, upon receiving the call, neither consent to it nor agree to pay capitation tax, it is then incumbent on the Muslims to call upon God for assistance, and to make war upon them, because God is the assistant of those who serve Him, and the destroyer of His enemies, the infidels, and it is necessary to implore His aid upon every occasion; the Prophet, moreover, commands us so to do.”
Shafi’i School, scholar Abu’l Hasan al-Mawardi (d. 1058):
“The mushrikun [infidels] of Dar al-Harb (the arena of battle) are of two types: First, those whom the call of Islam has reached, but they have refused it and have taken up arms. The amir of the army has the option of fighting them…in accordance with what he judges to be in the best interest of the Muslims and most harmful to the mushrikun… Second, those whom the invitation to Islam has not reached, although such persons are few nowadays since Allah has made manifest the call of his Messenger…it is forbidden to…begin an attack before explaining the invitation to Islam to them, informing them of the miracles of the Prophet and making plain the proofs so as to encourage acceptance on their part; if they still refuse to accept after this, war is waged against them and they are treated as those whom the call has reached…”
Some Muslim apologists say that Jihad has nothing to do with imposing anything on anyone because it really means “inner spiritual struggle” against evil. However, although it is true that Jihad literally means “struggle”, there is clear evidence that a violent military struggle has always been part of the meaning–in fact, the greater part of the meaning–of Jihad. And the goal of that struggle is subjugating us beneath the full weight of an Islamic State.