Is government a sin because people are ruling over other? What does the Bible say about this?
Government in itself is not a sin. The Bible is clear that God is the one who appoints governments. God who is the Sovereign One ordains or appoints all the rulers. Believers are called to subject ourselves to authorities (Rom 13:1-7) When Paul wrote this letter it was the evil Roman emperor Nero who was in power and yet Paul exhorted the Romans to submit themselves to his authority.Paul exhorts that as long as we are in the right path we do not need to fear authorities. God may judge people through the human authorities. So government is in the plan of God in ruling over the nations.
Just because people are ruling over others does not mean it is sin. But when rulers misuse the authority and fail to rule properly then it is sin. The rulers on their part need to acknowledge that they are accountable to God and therefore act as one who is representing God. The biblical model of leadership is servant leadership. Yet there are many countries in the world where the rulers do misuse authority but still as Christians in those countries we ought to subject to them. However there is still room for peaceful protests when those rulers are going against God but we cannot blatantly defy authorities because God is the one who placed them there.
