Therefore St. Peter says here, as ye would be pure and have complete sanctification, continue to contend with your evil lusts. So also Christ says in the Gospel of John xiii.: "Whoever is washed, must also wash his feet;" it is not enough that his head and hands be clean, therefore he would yet have them wash their feet.
But what does St. Peter mean, in that he says, refrain from the lusts that war against the soul? This is what he would say: You are not to imagine that you can succeed by sports and sleep. Sin is indeed taken away by faith, but you have still the flesh which is impulsive and inconsiderate; therefore take good care, that ye overcome it. By strong effort must it be; you are to constrain and subdue lust, and the greater your faith is, the greater will the conflict be. Therefore you should be prepared and armed, and should contend therewith without intermission. For they will assault you in multitudes, and would take you captive.
Hence St. Paul says, also, Rom. vii.: "I have a desire toward the law of God after the inward man; but I find another law in my members, which opposes itself to the law in my spirit, and takes me captive, that I cannot do as I would,"—as though he had said, I fight indeed against it, but it will not finally yield. Therefore I would gladly be free, but in spite of my wishing it, it may not come to pass. What then am I to do? "Wretched man that I am, (says he,) who shall deliver me from the body of this death." In this same manner, also, all the saints cry out. But those people who are without faith, the devil leads in such a way that he permits them only to enter on sinful courses, to follow him and make no opposition. But as to the others, he thinks, I have already taken them captive by unbelief. I will permit them then to go so far only, as to do no great sin and have no great assault and be kept from swearing and knavery.
But believers have always opposition enough,—they must ever stand in the (attitude of) struggle. Those who are without faith and have not the Spirit, do not feel this, nor do they have such an experience; they break away and follow their wicked lusts; but as soon as the Spirit and faith enter our hearts, we become so weak that we think we cannot beat down the least imaginations and sparks (of temptation), and see nothing but sin in ourselves, from the crown of the head, even to the foot. For before we believed, we walked according to our own lusts, but now the Spirit has come and would purify us, and there arises a conflict. Here the devil, the flesh, and the world, oppose themselves to faith; whereof the prophets complain, here and there, in the Scriptures.
Wherefore St. Peter here means, that the strife does not take place in sinners, but in believers, and gives us an encouragement, inasmuch as when we are on our guard against wicked lusts, we are repelling them. If thou, then, hast wicked thoughts, thou shouldest not on this account despair; only be on thy guard, that thou be not taken prisoner of them. Our teachers have proposed to relieve the matter in this way (by directing,) that men should torture themselves until they had no more evil thoughts, that they might be at last bold and free. But you are to understand, if you are a Christian, that you must experience all kinds of opposition and wicked dispositions in the flesh. For wherever there is faith, there come a hundred evil thoughts, a hundred strugglings more than before; only see to it that you act the man, and not suffer yourself to be taken captive; and continue to resist, and say, I will not, I will not. For we must here confess, that the case is much like that of an ill-matched couple, who are continually complaining of one another, and what one will do the other will not.
That may yet be called a truly christian life that is never at perfect rest, and has not so far attained as to feel no sin, provided that sin be felt, indeed, but not favored. Thus we are to fast, pray, labor, to subdue and suppress lust. So that you are not to imagine that you are to become such a saint as these fools speak of. While flesh and blood continue, so long sin remains; wherefore it is ever to be struggled against. Whoever has not learned this by his own experience, must not boast that he is a Christian.
Hitherto we have been taught, that when we made confession, or joined ourselves to some spiritual institution, we were at once pure and needed no longer to contend with sin. They have said, moreover, that baptism purifies and makes holy, so that nothing evil remains in the person. Then they have thought, "now will I have a pleasing rest," but the devil has come and assaulted them worse than before. Therefore understand the thing well, though you confess and permit yourselves to receive absolution, you must do even as the soldier, who in battle runs upon the points (of the javelins); whenever the critical moment approaches, and the conflict rages, compelling him to strike right bravely, as if to repel outrage, then he must draw out his sword and lay about him; but while the strife threatens only, so long must there be untiring vigilance. So, although you have been baptized, be on your guard, inasmuch as you are not safe for an hour from the devil and from sin, even though you think you will have no more assaults.
Therefore a christian life is nothing else but a conflict and encampment, as the Scripture says; and therefore the Lord our God is called the Lord of Sabaoth,—that is, a Lord over the hosts. So also, Dominus potens in prælio—the Lord mighty in battle.
And thereby He shows how powerful He is, that He permits His people to be exposed in the conflict and rush upon the points (of the javelins). Yet so that while the trumpets are ever sounding He is ever observant, (saying) beware here, beware there; thrust here, strike there. Besides, it is a lasting conflict, in which you are to do all that you can, so that you may strike down the devil by the word of God. We must therefore ever make resistance, and call on God for help, and despond of all human powers.—Now follows further:
V. 12. And lead an honest life, that those who have slandered you, as evil-doers, may see your good works and praise God. Mark now what an excellent order St. Peter has observed. He has already taught us what we should do in order to subdue the flesh with all its lusts. Now he teaches us again why this should be. Why should I subdue my flesh? that I may be saved? No, but that I may lead an honest life before the world. For this honest life does not justify us, but we must first be justified and believe before we attempt to lead an honest (pious) life. But as to outward conduct, this I am not to direct to my own profit, but that the unbelieving may thereby be reformed and attracted, that they through us may come to Christ; which is a true mark of love, though they slander and asperse us, and hold us as the worst wretches. Therefore we should exhibit such an excellent course of action, that men shall be compelled to say, Certainly they cannot be blamed.