Several teachings of the Bible show that “government should compel religion” is an incorrect view, one that is contrary to the teachings of the Bible itself.
1. Jesus distinguished the realms of God and of Caesar
The first biblical argument against the “compel religion” view comes from Jesus’ teachings in Matthew 22. Jesus’ Jewish opponents were trying to trap him with the question, “Is it lawful to pay taxes to Caesar, or not?” (Matt. 22:18). To say “yes” to Roman taxes ran the risk of appearing to support the hated Roman government. To say “no” to Roman taxes would make Jesus sound like a dangerous revolutionary against Rome’s power. Taking his opponents by surprise, Jesus said, “Show me the coin for the tax,” and “they brought him a denarius” (v. 19). After that, here is how the teaching unfolded:
And Jesus said to them, “Whose likeness and inscription is this?” They said, “Caesar’s.” Then he said to them, “Therefore render to Caesar the things that are Caesar’s, and to God the things that are God’s” (Matt. 22:20–21)…
This is a remarkable statement because Jesus shows that there are to be two different spheres of influence, one for the government and one for the religious life of the people of God. Some things, such as taxes, belong to the civil government (“the things that are Caesar’s”), and this implies that the church should not try to control these things. On the other hand, some things belong to people’s religious life (“the things that are God’s”), and this implies that the civil government should not try to control those things…
In Jesus’ statement about God and Caesar, he established the broad outlines of a new order in which “the things that are God’s” are not to be under the control of the civil government (or “Caesar”). Such a system is far different from the Old Testament theocracy that was used for the people of Israel. Jesus’ new teaching implies that all civil governments—even today—should give people freedom regarding the religious faith they follow or choose not to follow and regarding the religious doctrines they hold and how they worship God. “Caesar” should not control such things, for they are “the things that are God’s.”
Grudem, Wayne (2010-09-14). Politics - According to the Bible: A Comprehensive Resource for Understanding Modern Political Issues in Light of Scripture (pp. 25-26). Zondervan. Kindle Edition.