Church people are typically deceived.

James 1:22 KJV

But be ye doers of the word, and not hearers only, deceiving your own selves.

Learning the Bible, for example, at church, but not obeying it, causes people to be deceived. Church people almost never make permanent changes to their everyday lifestyles, based on what they learn from the Bible. They just keep on doing what they have always done, what they are used to, what those around them are doing. So they are deceived about many things.

Most disturbing is they are deceived about their salvation from God's wrath. They swear they are saved, and would never, ever question it, but their lives have no evidence of their actually being saved. They think, talk and look almost like unsaved people.