Shooting up a hospital full of sick patients as an individual is morally wrong. Putting on a uniform and obeying an order to drop a bomb on that same hospital is equally morally wrong. Distance and the use of technology do not magically change murder into warfare. If we want to live as Christians, die as Christians, and enjoy eternal life with Christ, then we must wage war as Christians. We must demand that same moral behavior out of any nation we support in any conflict. To do otherwise is to immeasurably harm our own souls.

We can gain some further insight into the Orthodox teaching on war from the War and Peace section of document The Basis of the Social Concept of the Russian Orthodox Church https://orthodoxreflections.com/can-christians-support-the-intentional-murder-of-civilians-in-war/