“All believers are brothers, so make peace between your brothers and be mindful of your duty to Allah that you may be shown mercy.” (Sura 49:11)
and: “In case two parties of the believers fight against each other, bring about reconciliation between them. If, however, one of them persists in belligerence and transgresses against the other, bring your collective might to bear upon the one that transgresses to force him until he agrees that his dispute […]