Lead kindly light…
I say, then, Theology is the fundamental and regulating principle of the whole Church system. It is commensurate with Revelation, and Revelation is the initial and essential idea of Christianity. It is the subject-matter, the formal cause, the expression, of the Prophetical Office, and, as being such, has created both the Regal Office and the Sacerdotal. And it has in a certain sense a power of jurisdiction over those offices, as being its own creations, theologians being ever in request and in employment in keeping within bounds both the political and popular elements in the Church’s constitution,—elements which are far more congenial than itself to the human mind, are far more liable to excess and corruption . .
[from Lectures on the Prophetical Office I