Erastianism is a big grown-up word that talks about how the government and the church work together.
When we go to church, we learn about God and all the good things that we should do. But sometimes, the government also wants to be involved in making rules and telling people what to do. That's where erastianism comes in.
Erastianism is when the government thinks they should have more control over the church. In some places, the government decides who can be a bishop or a priest, and they also make rules about what the church can and cannot do.
Some people think this is a good thing because it means that everyone is following the same rules and working together. But others think it's not so good because the government shouldn't have control over something that's supposed to be about faith and belief in God.
Overall, erastianism is a big word for a complicated idea about how the government and the church relate to each other. Some people like it, and some people don't. But what's most important is that we all remember to be kind and respectful to each other, no matter what we believe.