Posted on August 6th, 2012
Moreover, it is not without purpose and beside the point when Holy Scripture states that Isaac married Rebecca when he was 40 years old. For it points out that he did not take a wife in the well-known first passion of youth but stood firm for a considerable time in his battle against and victory over the flesh and the devil. For the accounts and the experience of individuals attest how great the impatience of lust is in youth, when the urgent sensation of the flesh begins and the one sex has an ardent desire for the other. This is a malady common to the entire human race, and those who do not resist its first flames and do not suppose that there is something for them to endure, plunge into fornication, adultery, and horrible lusts; or if they take wives rashly and ill-advisedly, they involve themselves in perpetual torture. Accordingly, Isaac endured that conflict and contended most valiantly with the flame and his flesh, because he was a true and complete human being just as we are. Moreover, our nature has been created in such a way that it feels the passions of the flesh at about the twentieth year. To endure and overcome those passions up to the fortieth year is surely a heavy and difficult burden. In this last age our young people refuse to assume this burden; they are unwilling to have patience for a moderate period of time. Therefore if they take wives during those first manifestations of passion, the devil, who earlier inflamed them with lust, later on cools them down with a breath to the opposite effect and causes them to go to extremes in their hatred of the woman. Those things are truly diabolical. Therefore the heart should first be instructed by the examples of the fathers, in order that it may be able to undertake and keep up that first battle against the flesh. The maturer age, which has arrived at the years of manhood, has its own battles—battles that are greater. During adolescence love begins to learn, just as it is described in adolescents in the works of the comic poets. But the sacred accounts present examples in which the victory, and at the same time the battles against the flesh, are set forth. Thus Isaac, too, felt the flames of lust just as other adolescents do. But he was taught by his father that one must Contend against these flames, first by reading Holy Scripture and praying, and then by working, being temperate, and fasting. These should be the exercises of adolescents, at least for one year or two, in order that those who are no longer able to be continent may learn nevertheless what the endurance of lust means. For this, too, is endurance and martyrdom, just as some assume several kinds of martyrdom, among which they count a rich, generous, and chaste young man. Indeed, this man is surely a martyr, because he is crucified every day by the passions of his flesh.
-Luther, AE 4