From the Word
O men, how long shall my honor suffer shame? How long will you love vain words, and seek after lies?
To have vanity is not the greatest of evils, for every man is vain, and there is nothing new under the sun, and though it be an evil, it is bearable. For there is not one saint that does not hope, trust, desire, fear, love and hate, more or less, in a way and manner that he ought not. But this body of sin and death, these laws of sin, these vanities, he ought to hate, not to love, nor take pleasure in them. To use the comfort and help of a creature is not sin, nor wrong; but to love them and rest in them alone, and from a love of them, not to trust in God, is an ungodly sin.
Hence, nothing more pestilential and destructive can be taught a Christian than moral philosophy and the decrees of men, if they be so set before him as to make him believe that he can walk in and by them so as to please God. For by such instruction it will come to pass that, relying on this wisdom, he will judge, condemn, and persecute whatever he sees is against him, and will thereby reject the cross of Christ and utterly despise the way of God, which is in its best and most prosperous state when we are following, as through a desert and wilderness, Christ in a pillar of fire.
But all these things are better understood by experience in time of suffering and adversity than they can possibly be described in words, or imagined by the heart. If the affections and thoughts of men are without faith in God, they are without the Word of God; if they are without the Word of God, they are without truth. Thus all things which are without faith are vanities and lies; for faith is truth by the Word of truth in which it believes and to which it cleaves by believing. The true meaning of this verse then is, that all are ungodly idolaters and polluters of the glory of God who under any tribulation draw back from faith, hope and love, to a confidence and comfort in created things.
Luther, Martin, and John Sander. Devotional Readings from Luther’s Works for Every Day of the Year. Augustana Book Concern, 1915, pp. 214–15.