Bismillahi Al-Rahmani Al-Rahim

A Question About The Big J

Assalamu alaikum wrt wbt

What is the mainstream Hanbali view on defending lands which are historically part of Dar Al-Islam?

Is it considered fard kifaya or fard ayn - to whom has the takleef spread?

jazakallah khayr

[Note: reworded slightly.]

wa `alaykum al-salam wa rahmatullahi wa barakatuhu

In general, it is a group obligation: if there are enough people it ceases being obligatory on the rest, though it is still a sunnah. Typically, when enough people do not do it, it becomes personally obligatory on those people who are closest, then next closest, and so on. While permission from the Imam (with a big letter i) is not required since this is self defense and coming to the aid of fellow Muslims, all other rules still apply. And lest anyone get wild ideas to make up for shirking this duty: the rules of Muslims who have immigrated to Dar Al-Harb with amnesty still apply.

And Allah knows best.

wa al-salamu `alaykum