Prudence is of two sorts, — human and Christian. Human prudence, which is also called the prudence of the flesh and of the world, is that which has no other aim than what is temporal, thinks only of arriving at its end, and makes use of such methods and sentiments alone as are human and uncertain. Christian prudence consists in judging, speaking, and acting that way in which the Eternal Wisdom, clothed in our flesh, judged, spoke, and acted, and in guiding ourselves in all cases according to the maxims of the Faith, never according to the fallacious sentiments of the world, or the feeble light of our own intellect. -St. Vincent de Paul
St. Vincent de Paul never used any but the Christian kind of prudence, so that it is no wonder that he was considered to have a rare and solid wisdom. Though his intellect was keen and clear enough to penetrate things to the bottom, and discover all their relations, yet he never trusted to his own light, till he had compared it and found it to agree with the maxims taught us by our Savior, which are the only rule by which to form a sure and certain judgment. So he never began to do anything of importance, or gave answers or advice to others, without first turning his eyes upon Jesus Christ, to find some act or word of His upon which he might securely rest the decision he was about to make.
Text from A Year With the Saints (New York: P.J. Kenedy & Sons, 1891).