Augustine of course stood squarely for the Pauline principle, having told us that the whole of history consisted of one deadly, no-give, no-take combat between two “cities,” that of God and that of man, the “citizens” of the former kingdom being in basic disagreement with those of the latter on the respective questions of the beginning, the middle, and the end of history. To be sure, citizens of the kingdom of God must not press upon those of the kingdom of man what Jesus said to the Pharisees, namely, that they be of their father, the devil, since only Jesus knew the heart of man. Thus, His followers may speak only of the two opposing principles activating men. Similarly, it is not possible for them to predict in each instance whether a certain individual belongs to one kingdom or the other, as history is never and nowhere a finished product. Nonetheless, there are two main and exclusive tendencies in it: men are in their hearts either for or against the Christ whom Paul preached, and what is in their hearts will usually find expression in the sympathies manifested by their actions.
– Cornelius Van Til, Who Do You Say That I Am p.33-34