NO---It is not!
Throughout the Bible, warfare is presented as a grim reality in a cursed world. There are forces of evil that must be stopped, and bloodshed is sometimes the result. Whether a Christian should serve in the military is a matter of one’s own conscience, but killing an armed combatant in the context of warfare is not sin. "There is a time and season for everything, including war" (Ecclesiastes 3:8).
Throughout the Bible, warfare is presented as a grim reality in a cursed world. There are forces of evil that must be stopped, and bloodshed is sometimes the result. Whether a Christian should serve in the military is a matter of one’s own conscience, but killing an armed combatant in the context of warfare is not sin. "There is a time and season for everything, including war" (Ecclesiastes 3:8).