"You believe that God is one. You do well.
The demons also believe, and they tremble." (James 2:19)
They alone know how to believe in God who love God, who are Christians not only in name but also in action and [way of] life, because without love faith is empty. With love, it is the faith of a Christian —without love, the faith of a demon.—The Venerable Bede, "Commentary on James"