Jihad as warfare

The Qur’an asserts that if the use of force would not have been allowed in curbing the evils by nations, the disruption and disorder caused by insurgent nations could have reached the extent that the places of worship would have become deserted and forsaken. As it states:
And had it not been that Allah checks one set of people with another, the monasteries and churches, the synagogues and the mosques, in which His praise is abundantly celebrated would have been utterly destroyed.
—Qur'an, [Qur'an 22:40]
Javed Ahmed Ghamidi divides just warfare into two types:
Against injustice and oppression
Against the rejecters of truth after it has become evident to them
The first type of Jihad is generally considered eternal, but Ghamidi holds that the second is specific to people who were selected by God for delivering the truth as an obligation. They are called witnesses of the truth (Arabic:شهادة, see also Itmam al-hujjah); the implication being that they bear witness to the truth before other people in such a complete and ultimate manner that no one is left with an excuse to deny the truth. There is a dispute among Islamic jurists as to whether the act of being "witness" was only for the Companions of Muhammad or whether this responsibility is still being held by modern Muslims, which may entitle them to take actions to subdue other Non-Muslim nations. Proponents of Companions of Muhammad as being "the witness" translate the following verse only for the Companions while others translate it for the whole Muslim nation. As in Qur'an:
And similarly [O Companions of the Prophet!] We have made you an intermediate group[ so that you be witnesses [to this religion] before the nations, and the Messenger be such a witness before you.
—Qur'an, [Qur'an 2:143]
Similarly, proponents of Companions of Muhammad as being "the witness" present following verse to argue that Companions of Muhammad were chosen people as witnesses just as God chooses Messengers from mankind. As in Qur'an:
He has chosen you, and has imposed no difficulties on you in religion; it is the religion of your father Abraham. It is He Who has named you Muslims, both before and in this [Qur’an]: [He chose you so that] the Messenger may be a witness [of this religion] to you, and you be witnesses of this religion to non-Muslims [of your times].
—Qur'an, [Qur'an 22:78]
Following is the first verse of the Qur’an in which the Companions of Muhammad, who had migrated from Mecca were given permission to fight back if they were attacked:
Permission to take up arms is hereby given to those who are attacked because they have been oppressed – Allah indeed has power to grant them victory – those who have been unjustly driven from their homes, only because they said: “Our Lord is Allah”.
—Qur'an, [Qur'an 22:39]
The reason for this directive in Medina instead of Mecca considered by most Muslim scholars is that without political authority armed offensives become tantamount to spreading disorder and anarchy in the society. As one of Islamic jurist writes:
Among Kafayah obligations, the third category is that for which the existence of a ruler is necessary e.g., Jihad and execution of punishments. Therefore, only a ruler has this prerogative. Because, indeed, no one else has the right to punish another person.
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Directive of warfare
The directive of the Jihad given to Muslims in Qur'an is:
These verses told Muslims that they should not merely fight the Banu Quraish if they resist them in offering Hajj, but the Qur’an goes on to say that they should continue to fight the Banu Quraish until the persecution perpetrated by them is uprooted and Islam prevails in the whole of Arabia. Initially Muslims were required to fulfill this responsibility even if the enemy was ten times their might. Afterwards, the Qur'an reduced the burden of this responsibility. As in Qur'an:
Prophet! Rouse the believers to wage war. If there are twenty amongst you, patient and persevering, they will subdue two hundred: if a hundred, they will subdue a thousand of the disbelievers: for these are a people without understanding.
—Qur'an, [Qur'an 8:65]
[From] now, God has lightened your [task] for He knows that there is now weakness amongst you: But [ever so], if there are a hundred of you, patient and persevering, they will subdue two hundred, and if a thousand, they will subdue two thousand, with the leave of God: for God is with those who patiently persevere.
—Qur'an, [Qur'an 8:66]
Some interpret above verses that Jihad never becomes obligatory unless the military might of the Muslims is up to a certain level. In the times of Muhammad, when large scale conversions took place in the later phase, the Qur'an reduced the Muslim to enemy ratio to 1:2. It seems that Muslims should not only consolidate their moral character, but it is also imperative for them to build their military might if they want to wage Jihad when the need arises. The Qur’an gave a similar directive to Muslims of Muhammad times in the following words:
Muster against them all the men and cavalry at your disposal so that you can strike terror into the enemies of Allah and of the believers and others beside them who may be unknown to you, though Allah knows them. And remember whatever you spend for the cause of Allah shall be repaid to you. You shall not be wronged.
—Qur'an, [Qur'an 8:60]
While other scholars consider the later command of ratio 1:2 only for a particular time.
A policy was adopted regarding the extent of requirement that arose in wars that the Muslims had to fight. In the battles of Badr, Uhud and Tabuk, the responsibility was much more and each Muslim was required to present his services as a combatant. As in Qur'an:
Not equal are those of the believers who sit [at home] without any [genuine] excuse and those who strive hard and fight in the cause of Allah with their wealth and their lives. Allah has given preference by a degree to those who strive hard and fight with their wealth and their lives above those who sit [at home]. [In reality], for each, Allah has made a good promise and [in reality] Allah has preferred those who strive hard and fight above those who sit [at home] by a huge reward. Degrees of [higher] grades from Him and forgiveness and mercy. And Allah is Ever Forgiving, Most Merciful.
—Qur'an, [Qur'an 4:95]
Qur'an also states that turning backs in the battle field, except for tactical purposes, is a big sin and will bring wrath of God.[ As in Qur'an:
O you who believe! when you meet those who disbelieve marching for war, then turn not your backs to them. And whoever shall turn his back to them on that day-- unless he turn aside for the sake of fighting or withdraws to a company-- then he, indeed, becomes deserving of Allah's wrath, and his abode is hell; and an evil destination shall it be.
—Qur'an, [Qur'an 8:15]

The driving force
Islamic scholars agree that Jihad should not be undertaken to gratify one’s whims nor to obtain wealth and riches. Many also consider that it must also not be undertaken to conquer territories and rule them or to acquire fame or to appease the emotions of communal support, partisanship and animosity. On the contrary, it should be undertaken only and only for the cause of Allah as is evident from the words. As in Qur'an:
Those who believe, fight in the cause of Allah, and those who disbelieve, fight in the cause of Satan. So fight you against the friends of Satan. Ever feeble indeed is the plot of Satan.
—Qur'an, [Qur'an 4:76]
Prophet Muhammad, at various instances, also explained very forcefully this purport of the Qur’an:
Abu Musa Ash‘ari (rta) narrates that once a person came to the Prophet (sws) and said that some people fight for the spoils of war, some for fame and some to show off their valor; he then asked the Prophet (sws): “Which one of them fights in the way of Allah”. The Prophet (sws) replied: “Only that person fights in the way of Allah who sets foot in the battlefield to raise high the name of Allah”. Sahih Bukhari 2810
Abu Hurayrah (rta) narrates from the Prophet (sws): “I swear by the Almighty that a person who is wounded in the way of Allah – and Allah knows full well who is actually wounded in His way – he would be raised on the Day of Judgement such that his colour be the colour of blood with the fragrance of musk around him”. Sahih Bukhari 2803
Ibn Jabr narrates from the Prophet (sws): “A person whose feet become dust ridden because of [striving] in the way of Allah will never be touched by the flames of Hell”. Sahih Bukhari 2811
Sahal Ibn Sa‘ad says that the Prophet (sws) once said: “To reside in a border area for a day to protect [people] against an enemy [invasion] is better than this world and everything it has”. Sahih Bukhari 2892
Similarly as a reward for participation in such a strive, the Qur'an states:
Consider not those who are killed in the way of Allah as dead. Nay, they are alive with their Lord, and they will be provided for. They rejoice in what Allah has bestowed upon them of His bounty and rejoice for the sake of those who have not yet joined them, but are left behind [not yet martyred] that on them too no fear shall come, nor shall they grieve. They rejoice in a grace and a bounty from Allah, and that Allah will not waste the reward of the believers.
—Qur'an, [Qur'an 3:169]

Ethical limits
Main article: Rules of war in Islam
Islamic Law, based upon the Quran and practices of Muhammad has set down a set of laws to be observed during the lesser Jihad.
Qur'an forbids fighting in sacred month and similarly within the boundaries of Haram. But if non-Muslims disregard these sanctities, Muslims are asked to retaliate in equal measure. It is stated in Qur'an:
A sacred month for a sacred month; [similarly] other sacred things too are subject to retaliation. So if any one transgresses against you, you should also pay back in equal coins. Have fear of Allah and [keep in mind that] Allah is with those who remain within the bounds [stipulated by religion].
—Qur'an, [Qur'an 2:194]
Observance of treaties and pacts is stressed in Qur'an. When some Muslims were still in Mecca, and they couldn't migrate to Medina, the Qur'an stated:
And to those who accepted faith but did not migrate [to Madinah], you owe no duty of protection to them until they migrate; but if they seek your help in religion, it is your duty to help them except against a people with whom you have a treaty of mutual alliance; and Allah is the All-Seer of what you do.
—Qur'an, [Qur'an 8:72]
Similar reports are attributed to Muhammad:
Abu Sa‘id (rta) narrates from the Prophet (sws): “On the Day of Judgment, to proclaim the traitorship of a traitor and the betrayal of a person who betrayed his words, a flag shall be hoisted which would be as high as [the extent of his] traitorship”, and [the Prophet (sws) also said]: “Remember that no traitor and betrayer of promises is greater than the one who is the leader and ruler of people”. Sahih Muslim 1738

Objectives of warfare
According to verses [Qur'an 2:190], the Qur'an implies two objectives:
Uproot fitnah (فتنة) or persecution
Establish supremacy of Islam in the world

Against persecution
Directives for action against persecution and unbelief:
And fight them on until there is no more tumult or oppression, and there prevail justice and faith in Allah altogether and everywhere; but if they cease, verily Allah doth see all that they do.
—Qur'an, [Qur'an 8:39]
Also:
And what has come over you that you fight not in the cause of Allah, and for those weak, ill-treated and oppressed among men, women, and children, whose cry is: ‘Our Lord! Rescue us from this town whose people are oppressors, and raise for us from You one who will protect, and raise for us from You one who will help. [You should know that] those who believe fight in the cause of Allah, and those who disbelieve, fight in the cause of Satan. So fight you against the friends of Satan. Ever feeble indeed is the plot of Satan.
—Qur'an, [Qur'an 4:75]
Most Muslim scholars consider it an eternal directive and believe that all types of oppression should be considered under this directive. Similarly, if a group of Muslims commit unwarranted aggression against some of their brothers and does not desist from it even after all attempts of reconciliation, such a group according to the Qur’an should be fought with:
And if two parties or groups among the believers start fighting, then make peace between them both. But if one of them outrages against the other, then fight you against the one which outrages till it complies with the command of Allah. Then if it complies, make reconciliation between them justly, and be equitable. Verily! Allah loves those who are the equitable. The believers are brothers to one another. So make reconciliation between your brothers, and fear Allah that you may receive mercy.
—Qur'an, [Qur'an 49:9]
If Muslims do not have a state, then in such a situation, Muhammad while answering a question raised by one of his followers, directed Muslims to dissociate themselves from such anarchy and disorder:
I asked: If there is no state or ruler of the Muslims? He replied: In this situation, dissociate yourself from all groups, even if you have to chew the roots of a tree at the time of your death. Sahih Bukhari 7084

Supremacy of Islam in the Arabian peninsula
It is stated in Qur'an:
Indeed those who are opposing Allah and His Messenger are bound to be humiliated. The Almighty has ordained: ‘‘I and My Messengers shall always prevail’’. Indeed Allah is Mighty and Powerful.
—Qur'an, [Qur'an 58:20]
After Itmam al-hujjah (clarification of religion to the addressees in its ultimate form), Jews were the ones who were subdued first. They had been granted amnesty because of various pacts. Those among them who violated these pacts were given the punishment of denying a Messenger of God. Muhammad exiled the tribe of Banu Qaynuqa to Khyber and that of Banu Nadir to Syria. The power they wielded at Khyber was crushed by an attack at their strongholds. Prior to this, Abu al-Rafi and Ka'b ibn al-Ashraf were put to death in their houses. The tribe of Banu Qurayza was guilty of treachery and disloyalty in the battle of the Ahzab. When the clouds of war dispersed and the chances of an external attack no longer remained, Muhammad laid siege around them. When no hope remained, they asked Muhammad to appoint Sa'd ibn Mua'dh as an arbitrator to decide their fate. Their request was accepted. Since, at that time, no specific punishment had been revealed in the Qur’an about the fate of the Jews, Sa'd ibn Mua'dh announced his verdict in accordance with the Torah. As per the Torah, the punishment in such situations was that all men should be put to death; the women and children should be made slaves and the wealth of the whole nation should be distributed among the conquerors. In accordance with this verdict pronounced, all men were executed. John Esposito writes that Muhammad's use of warfare in general was alien neither to Arab custom nor to that of the Hebrew prophets, as both believed that God had sanctioned battle with the enemies of the Lord.
No other incident of note took place regarding the Jews until the revelation of At-Tawba, the final judgement, was declared against them:Fight those who believe not in Allah or the Last Day, nor hold that forbidden which has been forbidden by Allah and His Messenger, nor acknowledge the Religion of Truth, from among the People of the Book, until they pay the Jizyah with willing submission and are subdued.
—Qur'an, [Qur'an 9:29]
This directive related to both the Jews and the Christians. The punishment mentioned in these verses is a show of lenience to them because they were originally adherents to monotheism. However, they did not benefit from this lenience because after the death of Muhammad they once again allegedly resorted to fraud and treachery.[ Consequently, the Jews of Khyber and the Christians of Najran were exiled once and for all from the Arabian peninsula by Umar. This exile actually fulfilled the following declaration of the Qur’an about them:
And had it not been that Allah had decreed exile for them, He would certainly have punished them in this world; and in the Hereafter theirs shall be the torment of the Fire.
—Qur'an, [Qur'an 59:3]
When the polytheists of Arabia had been similarly subdued, it was proclaimed in At-Tawba that in future no pact would be made with them. They would be given a final respite of four months and then they would be humiliated in retribution of their deeds and would in no way be able to escape from this punishment. After this time limit, the declaration is made in the Qur’an:
And a declaration should be made from Allah and His Messenger to these people on the day of the great Hajj that Allah is free from [all] obligations to these Idolaters and so is His Messenger. So if you [O Idolaters!] repent, it is better for you, but if you turn away, then know that you cannot escape from the grasp of Allah. And give tidings [O Muhammad (sws)] of a painful torment to these disbelievers. Except those of these Idolaters with whom you have a treaty, and who have not shown treachery in it nor have supported anyone against you. So fulfill their treaty to the end of their term. Indeed, Allah loves those who abide by the limits. Then when the sacred months [after the Hajj] have passed, kill these Idolaters wherever you find them, and capture them and besiege them, and lie in wait for them in each and every ambush. But if they repent and establish the prayer, and give Zakah, then leave them alone. Indeed, Allah is Ever Forgiving, Most Merciful.
—Qur'an, [Qur'an 9:3]
After the Treaty of Hudaybiyyah, Muhammad himself singled out nations by writing letters to them. In all, they were written to the heads of eight countries. Consequently, after consolidating their rule in the Arabian peninsula, the Companions launched attacks against these countries giving them two options if they wanted to remain alive: to accept faith or to accept a life of subjugation by paying Jizya. None of these nations were considered to be adherents to polytheism, otherwise they would have been treated in the same way as the Idolaters of Arabia.