Civil strife includes wars between Muslim rulers and Muslim groups when both sides remain committed to the laws of Islam, as was the case with those who fought at the Battles of the Camel and Siffīn. They fought one another only because of misconceptions and circumstances that arose.
As for fighting the Khawārij, those who withhold zakat, and the people of Tā’if who did not regard usury as forbidden, these are fought until they submit to the laws established by the Prophet, peace and blessings be upon him. If they have a group that maintains resistance, there is no doubt that it is permissible to kill their captives, pursue those fleeing, and finish off their wounded. For if they remain in their lands persisting in their ways, the Muslims must go to their lands to fight them until all religion is for Allah alone.
These Tatars are not fought on account of the religion of Islam; rather, they fight people until they submit to their rule. Whoever submits to their rule is left alone, even if he is a polytheist, a Christian, or a Jew. Whoever does not submit is their enemy, even if he is among the prophets and the righteous. Allah has commanded the Muslims to fight His disbelieving enemies and to maintain allegiance to His believing servants.
Thus, all Muslims serving in the armies of Syria, Egypt, Yemen, and the Maghrib must cooperate in fighting the disbelievers. They may not fight one another merely for leadership and personal desires. The very least required of these Tatars is that they fight the disbelievers nearest them, refrain from fighting the Muslims nearest them, and cooperate with those Muslims in