A state church is a government-run religious system. State churches have been popular in many nations/cultures throughout Christian history, but the idea itself is not biblical.
In the Old Testament, one could argue that Israel had a “state church.” The whole nation existed to worship God and serve Him in the land. However, ancient Israel was a theocracy and differed from modern state churches, which are based on human ideas, plans, and politics. For example, Constantine the Great’s reforms, which eventually led to a state church, were based on political expediency and a desire for social stability. Even as he embraced Christianity, he did not have a firm grasp on theology and mixed it with other worldviews and the pagan beliefs of Rome. This led to endless conflict in the church with many real Christians being killed.
During the Middle Ages, an amalgamation of church and state, in the form of the Holy Roman Empire, held sway over all of Europe, with the popes choosing political leaders, starting Crusades, and setting up Inquisitions. Later, King Henry VIII established the Anglican Church to break away from the authority of the Catholic Church, which prohibited divorce (and the king wanted to end his marriage). Thus was born another state church. In both Rome and England, the danger of a state church is evident: people who know nothing of Christ are suddenly “Christian” by virtue of the fact they are part of the state. Biblical Christianity always suffers by attempts to make it “official” in a nation.
The idea behind some state churches was seek to set up Christ’s kingdom before the return of Christ, but that is simply not what Christians have been called to do. When Jesus walked the earth, His disciples thought He would set up the kingdom and reign as king immediately, but Jesus told them a parable to counter that notion (Luke 19:11–27). He later told them, “It is not for you to know the time and the order of events which the Father has kept in his control” (Acts 1:7). This essentially means “not yet.” During one of His trials, Jesus told Pilate, “My kingdom is not of this world. . . . But now my kingdom is from another place” (John 18:36). His followers remain “sojourners and exiles” in this world (1 Peter 2:11). At the second coming, Jesus will reign (Revelation 20:6); until then, “God has given us this task of reconciling people to him” (2 Corinthians 5:18, NLT), not of setting up an earthly, political kingdom.
Finally, the Bible calls believers to worship God “in spirit and truth” (John 4:24). A state church will always devolve into empty formalism and tradition, creating a form of cultural Christianity and producing nominal Christians. Christians should respect and obey the government (Romans 13:1–7), but we are not called to create governments or legislate people into heaven through a state church. Ours is primarily a spiritual battle instead of a political one (2 Corinthians 10:4).
History shows that human-run systems will fail, and state churches are often created and maintained to achieve human goals. The Bible reveals the kingdom of God will be established by Christ upon His return; it is not dependent upon believers’ attaining power in the present. State churches may change the behavior of citizens—historically, through coercion—but they rarely reach the heart.