Is mental instability caused by demon possession?

1 Samuel 18:10

What is an evil spirit of the Lord?

Judges 9:23, 1 Samuel 16:14-16, 18:10, 1 Kings 22:22

Why did Eli think that Hannah was drunk?

1 Samuel 1:1-15

What is the type or shadow of the lamp of God that also went out in 1 Samuel 3:3?

1 Samuel 3:3

Why was David a “man after God’s own heart?”

1 Samuel 13:14

Throughout 1 Samuel 16 the KJV repeatedly reads, “Neither hath the Lord chosen this.” My question is: what is “this?”

1 Samuel 16:7-10

Why did David encourage himself in the book of 1 Samuel 30?

1 Samuel 30:1-6