What does that have to do with Israel attacking Palestine and occupying their country?
Everything, actually. It has everything to do with the islamist concept of waqf.
While a sense of patriotism for homeland isn't completely nonexistent in the Islamist mind-set, it is subordinate to striving in the way of muhammud ( swish) / Allah. All so-called "Muslim land", or dar al-Islam is a waqf, which is an endowment from God. The land is "Muslim land " in perpetuity. Infidel land, or dar al-Harb/Kufar is simply land not yet conquered in the name of Islam.
The issue of Palestine is fundamentally about land that islamists view as an entitlement from god. The other affront to the Medieval islamist mindset is a Jewish state in "Muslim lands". The Koran had many verses denigrating the Jews and islamism is thoroughly incensed that the Jews control land they feel an entitlement to.