Question: Is it permissible for a Christian to be in the police and carry a gun on the job?
Answer: Yes. Romans 13:1-4 tells us that God has authorized civil governing authorities. They bear the sword, verse 4 tells us, to punish those who do wrong. God has authorized civil authorities to punish criminals. Usually this is done through process of law, but laws also authorize the police to take potentially lethal action in certain situations.