27 But now hear, what I trust I shall by this time more easily persuade you of. In a matter of religion, that is, of the worship and knowledge of God, they are less to be followed, who forbid us to believe, making most ready professions of reason. For no one doubts that all men are either fools or wise. But now I call wise, not clever and gifted men, but those, in whom there is, so much as may be in man, the knowledge of man himself and of God most surely received, and a life and manners suitable to that knowledge; but all others, whatever be their skill or want of skill, whatever their manner of life, whether to be approved or disapproved, I would account in the number of fools.
And, this being so, who of moderate understanding but will clearly see, that it is more useful and more healthful for fools to obey the precepts of the wise, than to live by their own judgment? For everything that is done, if it be not rightly done, is a sin, nor can that any how be rightly done which proceeds not from right reason. Further, right reason is very virtue. But to whom of men is virtue at hand, save to the mind of the wise? Therefore the wise man alone sins not. Therefore every fool sins, save in those actions, in which he has obeyed a wise man: for all such actions proceed from right reason, and, so to say, the fool is not to be accounted master of his own action, he being, as it were, the instrument and that which ministers to the wise man.
Wherefore, if it be better for all men not to sin than to sin; assuredly all fools would live better, if they could be slaves of the wise. And, if no one doubts that this is better in lesser matters, as in buying and selling, and cultivating the ground, in taking a wife, in undertaking and bringing up children, lastly, in the management of household property, much more in religion. For both human matters are more easy to distinguish between, than divine; and in all matters of greater sacredness and excellence, the greater obedience and service we owe them, the more wicked and the more dangerous is it to sin.
Therefore you see henceforth that nothing else is left us, so long as we are fools, if our heart be set on an excellent and religious life, but to seek wise men, by obeying whom we may be enabled both to lessen the great feeling of the rule of folly, while it is in us, and at the last to escape from it.
Source: On the Profit of Believing (New Advent)