Shaykh Alee al-Hadaadee said, “Allaah, the Most High, said, “Those who are at war with Allaah and His messenger and spread corruption in the earth; they will be killed, or they will be hung, or their hands and their legs will be cut off, or they will be removed from the earth.”
Those people who are caught or take part in this activities, like bombings, which take innocent lives, their punishment [under Islamic law] is death, as they are individuals who spread corruption in the society.
They are not allowed to remain. That is why Allaah commanded that the people who do these types of acts [the Khawarij] be killed.
Also if they do not repent from these types of acts then in the hereafter there is waiting for them a severe torment.” Ref: masjidbinbaz.co.uk
Posted by Abdul Kareem Ibn Ozzie