Two terms that seem not to go together are 'holy' and 'war', though over the last millennium they have been paired countless times, and with gruesome results. It doesn’t make a difference whether we are talking about a so-called Holy Crusade or Jihad, it’s been the same thing with the same result.
The problem has not been a lack of understanding of the word "war"; that seems to come quite naturally to those who have taken up the banner of a Crusade or Jihad. The problem, of course, is the terrible lack of understanding of the concept of holiness [the concept of kedushah].
Ultimately, it is a question of what many call human dignity [derech eretz] which literally means “way of the land,” but which usually means good manners [....]
Admittedly, being holy [kiddush] can have its violent moments. For example, when the Jewish people [commanded by God] conquered Canaan, they were supposed to have wiped out the entire Canaanite nation, men, women, and children. They were not supposed to have shown any mercy, even though, in the end, they did.[Although] the war was commanded by God, [it was] reluctantly carried out by the Jewish people.
[The difference with other nations' holy wars,] they were not [commanded by God] and were carried out enthusiastically by those enlisted to fight. Ever listen to the people who are being trained for Jihad suicide attacks, or their relatives who support them? Enthusiasm is not the word.
[...] taking a look at the leaders who ordered the Crusades, or those who today encourage Jihad, human dignity seems to be lacking. They are dogmatic to an extreme, and show no concern for any life other than their own. The similarities between the way that the Muftis preach Jihad to their adherents and the way Hitler preached world domination to his people, are striking. There is plenty of pride, but nary a hint of [derech eretz or] human dignity.
Hence, the Holy Roman Empire was far more figurative than actual. The slaughtering that took place in the name of one god or another was as humanly undignified as you can get. “Holy” and “Roman” went together about as well as “Holy” and “War” do today, and with the same results.
Is it a coincidence that the Jewish people rarely did something similar, and when they did, it was on command of God and they showed unwarranted mercy? Is it by chance that the concept of a crusade, such as those carried out for hundreds of years in the name of spreading Christianity, does not exist in the Jewish lexicon? Is it simply recklessness that makes Israelis defend themselves today while trying, at great risk to themselves, to not harm those who are not directly members of those perpetrating acts of war against the State of Israel? Yet, those who do wage war against us do so joyfully and indiscriminately, they murder soldier and non-soldier, men, women, and children.
Ironically, the detractors of the Jewish people, especially today, like to argue just the opposite. They call the Israelis the aggressors, and criticize them for barbaric acts of war against a harmless and innocent people. Not only do they not feel bad about perpetrating such a lie, they actually feel good about themselves by taking it up and fighting for it. How undignified can you get?
Then again, many of these people would have no problem cheating on tax returns [....] The societies from which these people tend to come have stripped away much of human dignity, catering to base instincts rather than the Godly side of man. No wonder they can side with the wrong underdog.
In fact, when one ponders the spiritual level of Western society, and considers a term that best sums up that level, “holy” is not a term than comes to mind. In fact, nothing will break up a party faster than, “Hey, let’s do something holy now ....”
When the truth is the greatest asset in a person’s life, and they have the intellectual and emotional capacity to pursue it and accept it when they find it, and reject all the placebos along the way, a person will naturally have self-dignity. And, a person with self-dignity will automatically afford the same rights to others, except when the others are clearly evil.
* Source: Rabbi Pinchas Winston and Torah.org.