It may surprise some to learn that in the Bible, war itself is not portrayed as inherently wrong, immoral, or ungodly. There are times when God Himself authorizes and condones war as an instrument of justice.
God has given human governments the right to fight wars for self-protection and as a means of justice. The Old Testament is full of incidents where God Himself authorized war and even order the Israelites to wage war. And Scripture is clear in teaching that God still ordains government as the guardian of order and justice in society, and He still gives government the authority to punish evildoers, even by waging war, when necessary (Romans 13:1-4).
I am convinced God gave this power to governments because of His mercy. Otherwise, evil people would dominate. That is why a just war is an expression of divine righteousness. To turn away from justice in the name of peace is not an act of love; it is a refusal to love one's neighbor as oneself. To dispense with justice would never bring any kind of peace anyway. It would simply allow lawless people to dominate the world in a deadly fashion.
(Terrorism, Jihad, and the Bible, 88, 91, 98)