"Theology moves back and forth between two poles, the eternal truth of its foundations and the temporal situation in which the eternal truth must be received." [Paul Tillich, "Systematic Theology," 1951]
Theologian is first recorded late 15c., from O.Fr. theologien (14c.). A petty or paltry theologist is a theologaster (1620s), coined in M.L. by Martin Luther (1518).