His whole teaching is full of reference to it, setting forth its nature with every variety of illustration, enfolding it, as it were, with an exuberance of divine charity. But two conceptions run through every illustration, and are involved in its primary idea, nay, as this was the finished work of His Incarnation, so are they found in His adorable Person, from which His work springs. These conceptions are Unity and Visibility. As the mystery of the Incarnation consists in the union of the divine and human natures, in one Person, and in the assumption of a body, that is, matter, by the one uncreated, incomprehensible, and invisible Being, whereby He becomes visible, so Unity and Visibility are the unfailing marks of His Church, and enter into every image of it, in such a manner that without them the image loses its point and significancy. Accordingly He proclaims the Church which He was founding to be "the Kingdom of God," and "the Kingdom of Heaven," thus bringing before us the conceptions of order, government, power, headship on the one hand, dependence on the other, and a host of mutual relations between the Sovereign and the people, significantly remarking that "a kingdom which is divided against itself must fall." Now, a kingdom without unity is a contradiction in terms, and a kingdom of God on earth, which cannot be seen, would be for spirits and not for men. So He calls it a [4]"city seated on a mountain," which "cannot be hid," answering to His prophet's words, "the city of the great King," "His rest, and His habitation for ever." Here again are embodied the notions of order, government, conspicuous majesty, impregnable strength. Thus He inspires His apostle to call it[ 5]"the house of God, the pillar and ground of the truth." The house must have its head, the family their father; the knowledge of that father's will is the truth which rests upon the family as its support and pillar. Outside of the family that knowledge may be lost, together with the will to obey the father and to love him; but within it is a living tradition, "familiar to the ear as household words." As long as the Master and the Father is there, a perpetual light from His face is there too upon His children and His servants. Divide the house, or corrupt its internal life, and the idea of the house is destroyed; while an invisible house is an absurdity. Again, the Lord, calling Himself [6]"the Good Shepherd, who giveth His life for the sheep," terms His Church the sheepfold, and declares that as there is one shepherd, so there must be one fold. But, rising yet in nearness to the Divine Person of the Word Incarnate, from whose side sleeping on the cross she is moulded, the Church is called His Spouse, as united to Him in eternal wedlock, [7]"a great Sacrament," or mystery; and even yet more, His Body, as supported by the continual influx of her Head; and all her members are called "flesh of His flesh, and bone of His bones."