Good, but it must be done under the “right platform”.
Yes, it is allowed NOT in “religious wars” (Matthew 26:52) but in “Governmental Establishments”.
Example: Cornelius was a Roman Centurion (Acts 10:1) and John the Baptist did “NOT” ask Roman Soldiers to ‘quit their jobs as part of the repentance process’ (Luke 3:14).
Yes, one can be a ‘good Christian soldier’ like Cornelius (a Centurion leader in the army) during New Testament times even whilst serving under a “Christian-Jew OPPRESSING, UNFAIR, EXPLOITIVE Roman Army” as the example of Cornelius Proves – since he is considered ‘so righteous’ (in Good Deeds & Principles of his own) till even an ‘angel of God’ arranged a meeting between him and apostle Peter (as it is Described in Acts 10:1 – 8).
You only need to quit your “soldier job” if they force you to do an “injustice” against Biblical Principles. Can you see it?
“Every person is to be in subjection to the GOVERNING authorities. For there is no authority except from God, and those which exist are established by God.
Therefore whoever resists authority has opposed the ordinance of God; and they who have opposed will receive condemnation upon themselves.
For RULERS are not a cause of fear for good behavior, but for evil. Do you want to have no fear of authority? Do what is good and you will have praise from the same; for it is a minister of God to you for good. But if you do what is evil, be afraid; for it does not bear the SWORD for nothing; for it is a MINISTER of God, an AVENGER who brings WRATH on the one who practices EVIL.
Therefore it is necessary to be in subjection, not only because of wrath, but also for conscience’ sake.
For because of this you also pay taxes, for rulers are servants of God, devoting themselves to this very thing.
Render to all what is due them: tax to whom tax is due; custom to whom custom; fear to whom fear; honor to whom honor.” – apostle Paul (Romans 13:1 – 7, NASB)
Yes, no killing anyone in the Name of God/Religion.
The execution of Justice by opposing Governmental institutions during war who “fight for justice” (will be judged by God on that Great Day where if you’re the ‘Good guy-justified’, and if you’re the ‘oppressor-condemned’).
The average “citizens” (like us, the rest) need NOT participate in these as we “ought to lay down our lives if need be” (1 John 3:16) to demonstrate LOVE (“Perfection”, Matthew 5:38 – 48) instead of ‘Justice’ (Good, but NOT perfect).
Example: Who is ‘Joan of Arc’? She FOUGHT OPPRESSORS who INVADED her HOMELAND. Details Link below:
Highlight: “On May 29, 1431, the tribunal announced Joan of Arc was guilty of heresy. On the morning of May 30, she was taken to the marketplace in Rouen and burned at the stake, before an estimated crowd of 10,000 people. She was 19 nineteen years old. One LEGEND surrounding the event tells of how HER HEART SURVIVED the FIRE UNAFFECTED”
A secular song mentioning her name (Tal Bachman – She’s So High):