On The Holy Trinity by St. Augustine
Chapter 15.--They are Proud Who Think They are Able, by Their Own Righteousness, to Be Cleansed So as to See God.
20. There are, however, some who think themselves capable of being cleansed by their own righteousness, so as to contemplate God, and to dwell in God; whom their very pride itself stains above all others. For there is no sin to which the divine law is more opposed, and over which that proudest of spirits, who is a mediator to things below, but a barrier against things above, receives a greater right of mastery: unless either his secret snares be avoided by going another way, or if he rage openly by means of a sinful people (which Amalek, being interpreted, means), and forbid by fighting the passage to the land of promise, he be overcome by the cross of the Lord, which is prefigured by the holding out of the hands of Moses. For these persons promise themselves cleansing by their own righteousness for this reason, because some of them have been able to penetrate with the eye of the mind beyond the whole creature, and to touch, though it be in ever so small a part, the light of the unchangeable truth; a thing which they deride many Christians for being not yet able to do, who, in the meantime, live by faith alone. But of what use is it for the proud man, who on that account is ashamed to embark upon the ship of wood, to behold from afar his country beyond the sea? Or how can it hurt the humble man not to behold it from so great a distance, when he is actually coming to it by that wood upon which the other disdains to be borne?