Saul is the old state ruled by fear, the self that takes the present report of the senses as final. When that self is set aside, David takes the throne. David is the outer world turned obedient, the whole responsive scene that carries out an inner act and hands it back as accomplished fact. That is why he is called a man after God's own heart and the one who fulfils all the will. Whatever a person has imagined and quietly lived as already so, God owns as his own doing, and the world moves to complete it.
Jesse means the plain statement, I am. From that root the answering world is born. The imagined state assumed within is no private wish. That state is the will of the power inside you, and it arrives bringing everything that was claimed.