Jesus Christ came into the world to bring to men the true knowledge of God; for "God was in Christ reconciling the world unto Himself" (2 Cor. 5:19). He came to reveal to men the kingdom of God, -- to enunciate its principles, to manifest its spirit, to reveal its character. Of it He said: "My kingdom is not of this world" (John 18:36). "Except a man be born again, he can not see the kingdom of God" (John 3:3). And His apostles declared, "The kingdom of God is . . . righteousness and peace and joy in the Holy Ghost" (Rom. 14:17).
"My kingdom is not of this world." Every kingdom, every State, every government of men, is altogether of this world and of this world alone. How then can anybody be of any earthly kingdom or State and of the kingdom of God at the same time? Those who are of the church are of the kingdom of God, because the church is the church of God, and not of this world -- it is composed of those who are "chosen out of the world." Those who are of the State are of this world, because the State is altogether and only of this world.
And, indeed, were not "all the kingdoms of the world and the glory of them" offered to Jesus for His very own? Why did He not take them and rule over them and convert them and thus save them -- He could not, because to have taken them would have been to recognize "the god of this world," by whom they were offered. (Luke 4:5-8). And so, the kingdom of this world is offered ever only by Satan; and all who are Christ's will refuse it, as did our Example, and as did Moses, His chosen forerunner and type.
Christ was and is the embodiment of the church and of all Christianity. Therefore, and thus, in the Word of Christ, in the very principles of the cause of Christ, there is taught the separation of Church -- of Christianity -- and State as complete and as wide as in the separation between the kingdom of God and the kingdoms of this world; and that is as complete and as wide as is the separation between God and this world.
Accordingly, Christ says in another place, "Render therefore unto Caesar the things which are Caesar's and unto God the things that are God's" (Matt. 22:21). In that time the head of the Roman Empire, the personification of the world's power, was Caesar. And in that Roman world-system it was claimed that whatsoever was Caesar's was God's; because to all the people of that world-system Caesar was God. He was set before the people as God; the people were required to worship him as God; incense was offered to his image as to God. In that system the State was divine, and Caesar was the State. Therefore that system was essentially a union of religion and the State.