1 Samuel 16:15
And Saul’s servants said unto him, Behold now, an evil spirit from God troubleth thee.
Cross-reference
1 Samuel 16:1
Historical context
In 1 Samuel 16:1, God's rejection of Saul explains why the evil spirit now troubles him.
1 Samuel 18:10
Parallel
In 1 Samuel 18:10, the same evil spirit later causes Saul to attempt to kill David, showing the ongoing threat.