The Islamic Personality by Sheikh Taqīuddīn An-Nabahānī

The belligerent disbeliever is any disbeliever who has not entered in the pledge (dhimmah) of the Muslims, whether he was under a covenant or under security (must’amin) or was neither a mu’ahid nor a musta’min. If a treaty is contracted between the Islamic State and any kafir State, the citizens of this State are covenanted persons who are dealt with according to what is stated in the treaty that is between them and us, and all that is included in this is executed. Nevertheless, despite the existence of the treaty the covenanted disbelievers are not excluded from being belligerent disbelievers in the rule (hukman) because the mere conclusion of the treaty or its nullification by them or us returns their rule to the rule of the rest of the belligerent disbelievers. Due to this, selling them weapons and war materials is prevented if there is therein a strengthening for them against Muslims; however, if selling them weapons or war materials is not strengthening them against Muslims then their sale to them is not prevented particularly if the Islamic State becomes a manufacturer of weapons and sells like the great States today. If the treaty mentions the permissibility of selling them weapons and war materials, this condition is not fulfilled if it strengthens them against Muslims as it contradicts the Shar’a, and all conditions contradicting the Shar’a are void and not contracted.

As for where there is no treaty between them and us, they are belligerent disbelievers in reality whether they are at an active war with the Islamic state or no. They are not enabled to enter the Muslim land except by a specific security (for) each time and they are not enabled to reside in the Muslim land except for a specific and limited period. However, the difference between a belligerent disbeliever State which is fought in practice and a belligerent disbeliever State not being fought in practice is that with the belligerent disbeliever State fought in practice no treaty is contracted with her before the peace agreement and security is not given to any of its citizens except if he comes to listen to the speech of Allah or if he comes to become a dhimmi living in the Muslim land. This is contrary to the belligerent Disbeliever State not fought in practice as commercial, good neighbourliness and other treaties are contracted with her, and her citizens are given a security to enter the Islamic land for trade, recreation, tourism or other than that.