1 Corinthians 14:33 says God is not a God of confusion. The argument sets against it Isaiah 45:7, where God says he forms light, creates darkness, makes well-being and creates calamity, and 1 Samuel 16:14, where a harmful spirit from the LORD tormented Saul. It adds 2 Thessalonians 2:11, which says God sends a strong delusion so that people believe a lie.
The complaint is that the Bible makes God the author of calamity and deception while insisting he is not the author of confusion.
I form light and create darkness; I make well-being and create calamity; I am the LORD, who does all these things.
Isaiah 45:7
Now the Spirit of the LORD departed from Saul, and a harmful spirit from the LORD tormented him.
1 Samuel 16:14
Source: see Credits and references (no. 13, p. 10).