'Crazy' in the Bible

So David changed his behavior before them and acted like he was crazy in their presence. He scribbled on the doors of the gate, and let his saliva run down his beard.

“Look! You can see the man is crazy,” Achish said to his servants. “Why did you bring him to me?

Do I have such a shortage of crazy people that you brought this one to act crazy around me? Is this one going to come into my house?”

When Jehu came out to his master’s servants, they asked, “Is everything all right? Why did this crazy person come to you?”Then he said to them, “You know the sort and their ranting.”

The LORD made you a priest instead of Jehoiada the priest to serve in the LORD's Temple as an official against every crazy prophet, and to put him in stocks and restraints.