The Imām does not begin fighting them until they begin against him or gather for it; then he fights them until he disperses them.
تحفة الملوكZayn al-Dīn al-Rāzīفصل والخوارج يدعون إلى الاستسلام، وتكشف شبهتهم.
Chapter: The Khārijites — surrender, fighting, and rebel finance
If they have a unit he finishes off their wounded and pursues deserters of their commander; otherwise not.
Their dependants are not enslaved nor their wealth taken as spoils.
ويجوز القتال بأسلحتهم وركوب خيلهم عند الحاجة، ويحبس الإمام أموالهم حتى يتوبوا فيردّها عليهم.
Fighting with their weapons and riding their horses when necessary is lawful; the Imām seizes their wealth until they repent then returns it to them.
وما جبوه من الزكاة والعشر والخراج من البَلاد التي غلبوا عليها لم يثَن، ويفتى المأخوذ منه بإعادة الزكاة والعشر إن كان الآخذون أَغنياء بخلاف الخراج.
What they collected as zakāh, tithe, and khārāj from lands they controlled is not levied twice; fatwā is given that the party from whom [payments] were taken should repay zakāh and tithe if the collectors were affluent—unlike khārāj.
ولو قتل بعضهم بعضاً، ثم ظهرنا عليهم فهو هدر، ولو غلبوا على بلد فقتل رجلٌ من أهله رجلاً آخر ثمّ ظهرنا على البلد قبل استقرار ملكهم وإجراءِ أَحكامهم وَجَبَ القصاص وإلاّ فهو هدر.
If some of them kill one another and we prevail over them, no retaliation is due. If they conquer a town and a man of its people kills another man, then we conquer the town before their rule settles and their rulings take effect, retaliation is obligatory; otherwise no retaliation is due.
ولا يأثم العادل ولا يضمن بإتلاف مال الباغي أو نفسه، والباغي يأثم فيما يفعل بالعادل ولا يضمن.
The just party does not sin nor owe for destroying rebel wealth or life; the rebel sins for what he does to the just and owes nothing.
فلو قتلَ العادل الباغي وَرِثَه، ولو قتله الباغي وقال: قتلته محقاً وَرِثَه وإن قال: قتلت مبطلاً لم يرثه، والله أعلم.
If the just kills the rebel [the killer] inherits from him; if the rebel kills him claiming rightful killing [the rebel] inherits; if he says wrongful killing he does not inherit—Allah knows best.