It's a declaration of religious war.
Source: twitter.com
How many wars/conflicts have been started specifically over religion? I know the Crusades are a very well known one, but I’m trying to do more research to see any other significant ones that there have been.
There truly are dozens and dozens of them, all around the world. It's been going on for centuries.
And yes, even the Buddhists get in on the action.
Violence and religion go hand in hand. No, not all wars are or were religious in nature. Humans have been invading and attacking each other to acquire territory, resources and ensure the security of their own tribes and communities since the species arose.
But when you have divine knowledge that needs to be spread to others, or divine authority to carry out its will, the lives of those who stand in the way don't really matter.
“With or without religion, good people can behave well and bad people can do evil; but for good people to do evil - that takes religion.” - Steven Weinberg
Believers say all the time that non-believers are arrogant and selfish, because the believer is part of "something greater than ourselves," while non-believers are not.
Even though we can; whether that "something" is noble (e.g. the wellbeing of humanity, the planet) or indifferent and with no agenda (the universe itself).
Who are mere humans - heretics, no less - to stand in the way of a divine message, divine will, divine morality? To believe in "god" is to believe in "good," so those who don't aren't just outsiders, they're the enemy, resisting and fighting against "good." Believers are right and justified to destroy them.
As always, religion dehumanizes.
People try to dismiss the effect of religion in the Israel-Palestine conflict, that it's just territory, recognition and politics. However at the core, Islam declares the Jews to be "evildoers."
O believers, take not Jews and Christians as friends; they are friends of each other. Whoso of you makes them his friends is one of them. God guides not the people of the evildoers.
Abu Huraira reported Allah's Messenger (ﷺ) as saying:
The last hour would not come unless the Muslims will fight against the Jews and the Muslims would kill them until the Jews would hide themselves behind a stone or a tree and a stone or a tree would say: Muslim, or the servant of Allah, there is a Jew behind me; come and kill him; but the tree Gharqad would not say, for it is the tree of the Jews.
The trees and stones themselves will betray the Jews on Judgment Day. Yes, talking trees and stones. Just like the talking snakes, bushes and donkeys of Xianity.
For their part, Judaism declares the Jews to be the Chosen People. Which we learn in the book they wrote.
When you're certain that you're Chosen by god - essentially, "on the right side of history" - what won't you be prepared to do?
The religions themselves make it nigh on impossible for any kind of accord to be reached, at least, little more than temporarily.
And, as always, to make the implicit explicit, no, this isn't the sentiment of every believer. But that comes in spite of religious doctrine, not because of it. The canon, the religion, the ideology says what it says.
Of course, even a "traditional" religion isn't required. As Stalin and Mao demonstrate, a pseudo-religion which worships a messianic figure installed through a cult of personality will do the same thing. Mao's "Little Red Book" acts as scripture, their visages were as prevalent as Xian crucifixes, and both are worshipped to this day, embalmed and on display for pilgrims to venerate.
North Korea's Kim dynasty is an example of the same thing functioning in real time. The conflict between North Korea and, well, everybody, is essentially an intermittent pseudo-religious war.
Hope this helps in some way.
If Satan can lead a rebellion in heaven, then there can be aggression, jealousy, resentment, hatred and other types of non-paradise emotions in this perfect paradise.
Xian mythology cancels itself out.