It becomes one who is called to be a soldier, and to go a warfare, to endeavor to excel in the art of war. It becomes one who is called to be a mariner, and to spend his life in sailing the ocean, to endeavor to excel in the art of navigation. It becomes one who professes to be a physician, and devotes himself to that work, to endeavor to excel in the knowledge of those things which pertain to the art of physic. So it becomes all such as profess to be Christians, and to devote themselves to the practice of Christianity, to endeavor to excel in the knowledge of divinity.