By now, we have seen that hope and belief are necessary for faith, but just what is faith? One good definition is that faith is belief put into action.
The devils believe in one God, but without any hope, they cannot take any positive steps associated with that belief. A person may believe in God, but not feel that there is any hope for them. They too are incapacitated, and prevented from taking a positive action to realize their hopes, for they have no such hopes.