By Dr. Luke Arredondo, St. Philip Institute - If someone asks you to identify the single most important doctrine in Christianity, how would you reply? It’s probably not the principle of double effect. Could it be the fall of Adam and Eve? Creation itself? The infallibility of Scripture? All of those are fine and well, and very important for Christianity. But according to St. Paul, there is one teaching that stands out above all the rest. If this one teaching is true, it changes everything, and if it is not, then everything is a lie.