@marks won’t want to hear this but if I were on the side of ”Christians can serve in the military and in law enforcement” camp, I would appeal to the writings of the Nicene Church Fathers.
marks does have one good point: Stick to the Bible and don’t add to it.
A shift occurred in the thinking and teaching of the church in the 4th century. The beginning of Just War theory is located there. It comes to us from the church, not from Jesus and the apostles; not from the New Testament.
Both of my parents worked for the government. Both advised me not to go to work for the government when I graduated with a degree in Civil Engineering. I took their advice. For two years. Then I went on to have a thirty-year career in government (in environmental regulatory programs which didn’t involve using a weapon of the world.) Corruption was rampant. I refused to go along with it and paid a high price for it. Looking back on it, I think I made the wrong choice.
That’s all bridge under the water now.