The Bible Stance on War!

God is not against killing in all circumstances, but only murder. War is never a good thing, but sometimes it is a necessary thing. In a world filled with sinful people (Romans 3:10-18), war is inevitable. Sometimes the only way to keep sinful people from doing great harm to the innocent is by going to war.
Go and completely destroy those wicked people, the Amalekites; make war on them until you have wiped them out.” Obviously, God is not against all war. Jesus is always in perfect agreement with the Father (John 10:30),
In a world filled with sin, hatred, and evil (Romans 3:10-18), war is inevitable. Christians should not desire war, but neither are Christians to oppose the government God has placed in authority over them (Romans 13:1-4; 1 Peter 2:17). The most important thing we can be doing in a time of war is to be praying for godly wisdom for our leaders, praying for the safety of our military, praying for quick resolution to conflicts, and praying for a minimum of casualties among civilians on both sides (Philippians 4:6-7).

Sources:
https://www.gotquestions.org/war-Bible.html

https://www.openbible.info/topics/war

https://bibleresources.org/war/