In the Word of God we find numerous references to God as "THE LORD OF HOSTS." Host is another word for army. God Almighty is "THE LORD OF ARMIES."
This gets deeper than you might imagine. "God quickens all things." He is the Prime Mover of all beings and things in the Universe He created. He quickens the soldiers of opposing armies silmultaneously at the same time, totally controlling the outcome of battles and wars.
Since God Almighty controls the outcome of wars, it is wise for men to avoid war at all costs until there is no other alternative.
The enlightened King David knew God as the A and the Z of war, so, he wrote: "THOUGH AN HOST SHOULD ENCAMP AGAINST ME, MY HEART SHALL NOT FEAR: THOUGH WAR SHOULD RISE AGAINST ME, IN THIS WILL I BE CONFIDENT." (Psalm 27:3)
Moses and the children of Israel sang "GOD IS A MAN OF WAR" (EXODUS 15:3) after the LORD drowned Pharoah and his army in the Red Sea. It was obvious to them they didn't do it.
Understanding the great wonder of God quickening the soldiers of both armies as they go into mortal combat, gets into fine print when you consider King David saying, "HE TURNED THE EDGE OF HIS SWORD AND HAVE NOT MADE HIM TO STAND IN THE BATTLE." (Psalm 89:43) When God turned the edge of David's sword in battle, he was knocked down and nearly lost his life. This was such a close call, the Israelites would not permit David to go into combat ever again for fear of losing his angelic Light to rule over them.
They understood better how God is "THE LORD OF ARMIES."