Today is the feast of St. Alphonsus Liguori, Doctor of the Church. From his Practice of the Love of Jesus Christ:
The true lover of Jesus Christ keeps the eternal truths constantly in view, and orders all his actions according to them. Oh, how thoroughly does he who loves Jesus Christ understand the force of that saying of the Wise Man, Vanity of vanities, all is vanity; that all earthly greatness is mere smoke, dirt, and delusion; that the soul's only welfare and happiness consists in loving its Creator, and in doing his blessed will; that we are, in reality, no more than what we are before God; that it is of no use to gain the whole world, if the soul be lost; that all the goods of the world can never satisfy the human heart, but only God himself; and, in fine, that we must leave all to gain all. (p. 432)