This question emanates from the commandment, which says:  “Thou shall not kill” – Exodus 20:13

First of all, war conditions is not God’s will for any nation because it devastates what God has created. Now on the issue of Christian military men, I don’t want to be a judge on the matter because military men don’t murder in war but they fight in defense of their home country.

The defense of their home country may involve killing which I know is not good but now they’re doing it to save a larger community. If they don’t kill the enemies of the state, then everyone maybe killed by the enemies of the state. In my opinion, I don’t think that would be a sin but let’s leave matters such as this to the just Judge who knows better than we do.