Here is a passage from the book of Deuteronomy.

When you draw near to a city to fight against it, offer terms of peace to it. And if its answer to you is peace and it opens to you, then all the people who are found in it shall do forced labor for you and shall serve you. But if it makes no peace with you, but makes war against you, then you shall besiege it; and when the Lord your God gives it into your hand you shall put all its males to the sword, but the women and the little ones, the cattle, and everything else in the city, all its spoil, you shall take as booty for yourselves.

Granted, the Judeo-Christian God—unlike the 9/11 hijackers—here seems to favor sparing women and children. But this treatment is reserved for "cities which are very far from you." In nearer cities,

the cities of these peoples that the Lord your God gives you for an inheritance, you shall save alive nothing that breathes, but you shall utterly destroy them, the Hittites and the Amorites, the Canaanites and the Perizzites, the Hivites and the Jebusites, as the Lord your God has commanded; that they may not teach you to do according to all their abominable practices which they have done in the service of their gods, and so to sin against the Lord your God.

In contrast, the Quran—as interpreted by Mohamed—counsels sparing women and children, even in a holy war.