This high, noble, sweet work can easily be learned, if we perform it in faith, and as an exercise of faith. For if faith does not doubt the favor of God nor question that God is gracious, it will become quite easy for a man to be gracious and favorable to his neighbor, however much he may have sinned; for we have sinned much more against God. Behold, a short Commandment this, but it presents a long, mighty exercise of good works and of faith. Thou shalt not commit adultery. In this Commandment too a good work is commanded, which includes much and drives away much vice; it is called purity, or chastity, of which much is written and preached, and it is well known to every one, only that it is not as carefully observed and practised as other works which are not commanded. So ready are we to do what is not commanded and to leave undone what is commanded. We see that the world is full of shameful works of unchastity, indecent words, tales and ditties, temptation to which is daily increased through gluttony and drunkenness, idleness and frippery. Yet we go our way as if we were Christians; when we have been to church, have said our little prayer, have observed the fasts and feasts, then we think our whole duty is done. Now, if no other work were commanded but chastity alone, we would all have enough to do with this one; so perilous and raging a vice is unchastity. It rages in all our members: in the thoughts of our hearts, in the seeing of our eyes, in the hearing of our ears, in the words of our mouth, in the works of our hands and feet and all our body. To control all these requires labor and effort; and thus the Commandments of God teach us how great truly good works are, nay, that it is impossible for us of our own strength to conceive a good work, to say nothing of attempting or doing it. St. Augustine says, that among all the conflicts of the Christian the conflict of chastity is the hardest, for the one reason alone, that it continues daily without ceasing, and chastity seldom prevails. This all the saints have wept over and lamented, as St. Paul does, Romans vii: "I find in me, that is in my flesh, no good thing." II. If this work of chastity is to be permanent, it will drive to many other good works, to fasting and temperance over against gluttony and drunkenness, to watching and early rising over against laziness and excessive sleep, to work and labor over against idleness. For gluttony, drunkenness, lying late abed, loafing and being without work are weapons of unchastity, with which chastity is quickly overcome. On the other hand, the holy Apostle Paul calls fasting, watching and labor godly weapons, with which unchastity is mastered; but, as has been said above, these exercises must do no more than overcome unchastity, and not pervert nature.