Obedience unites us so closely to God that it in a way transforms us into Him, so that we have no other will but His. If obedience is lacking, even prayer cannot be pleasing to God.
Thomas AquinasReasoning is compared to understanding as movement is to rest, or acquisition to possession.... Since movement always proceeds from something immovable, and ends in something at rest, hence it is that human reasoning, in the order of inquiry and discovery, proceeds from certain things absolutely understood--namely, the first principles; and, again, in the order of judgment, returns by analysis to first principles, in the light of which it examines what it has found. Now it is clear that rest and movement are not to be referred to different powers, but to one and the same.
Thomas Aquinas