What defines this consensus, above all—what distiguishes orthodoxy from heresy, the central river from the delta—is a commitment to mystery and paradox.
Thus orthodox Christians insist that Jesus Christ was divine and human all at once, that the Absolute is somehow Three as well as One, that God is omnipotent and omniscient and yet nonetheless leaves us free to choose between good and evil. They propose that the world is corrupted by original sin and yet somehow also essentially good, with the stamp of its Creator visible on every star and sinew. They assert that God sets impossible moral standards and yet forgives every sin. They insist that faith alone will save us, yet faith without works is dead. And they propose a vision of holiness that finds room in God’s Kingdom for all the extremes of human life—fecund families and single-minded celibates, politicians and monastics, queens as well as beggars, soldiers and pacifists alike.
Time and again, in the early centuries Anno Domini, the councils of the Church had the opportunity to resolve the dilemmas and shore up the fragile syntheses—to streamline Christianity, rationalize it, minimize the paradoxes and the difficulties, make it more consistent and less mysterious.
In each instant, and in many more as well, they chose the way of mystery instead—or else they were bullied and arm-twisted into it, by mobs of emperors and polemicizing intellectuals. The process seemed haphazard at the time, but in hindsight it looks providential. In the choices they made and the arguments they rejected, the Fathers of the Church forged a faith whose doctrines speak to the intuition, nearly universal among human beings, that the true nature of the world will always remain just beyond our grasp. But they accomplished this without surrendering to an unintelligible mysticism or a crude anti-intellectualism. Indeed, this is perhaps the greatest Christian paradox of all—that the world’s most paradoxical religion has cultivated rationalism and scientific rigor more diligently than any of its rivals, making the Christian world safe for philosophy as well as fervor, for the study of nature as well as the contemplation of divinity.
—from Bad Religion: How We Became a Nation of Heretics by Ross Douthat, Prologue: A Nation of Heretics