Defending one’s self and what is related to it is an instinctive matter firmly established in man. The Shariah accepted this and commanded and encouraged people to do it, promising reward for doing it and punishment for ignoring it; this is because of its utmost importance to man’s happiness, the nations’ advancement and societies’ stability.
Defending the self against personal dangers may sometimes become a specific obligation (wajib ‘ayniy) and allowed in others, and if the person was incapable of stopping the danger to himself, it becomes obligatory on others to do so as an obligation under the conditions of sufficiency (wajib kifa’i). As for defending the homeland and similar public matters, its obligation is originally a wajib kifa’i, but it may become wajib ‘ayniy on some occasions.