You shall not commit adultery!
(Thomas Watson, "The Ten Commandments". This selection is longer, but it is needful in our immoral society. Though it particularly addresses adultery, it easily applies to any kind of immorality. This is the best article I have ever read, on how to deal with lust. Every man struggles with lust—so please forward this on.)
"You shall not commit adultery." Exodus 20:14
This commandment is set up as a hedge to keep out impurity; and those who break this hedge—a serpent shall bite them! The fountain of this sin is lust. God is a pure, holy being, and has an infinite antipathy against all impurity. We must take heed of running on the rock of impurity, and so making shipwreck of our chastity. The meaning of the commandment is not only that we should not stain our bodies with immorality—but that we should keep our souls pure. To have a chaste body—but an unclean soul, is like a beautiful face with a cancerous heart. "Be holy, for I am holy." 1 Peter 1:16.
There is a mental adultery. "Whoever looks on a woman to lust after her, has committed adultery with her already in his heart." Matthew 5:28. As a man may die of an inward bleeding—so he may be damned for the inward boilings of lust, if it is not mortified. That I may deter you from the sin of adultery, let me show you the great evil of it.
(1) Adultery is a thievish sin. It is the highest sort of theft. The adulterer steals from his neighbor, that which is more than his goods and estate; he steals away his wife from him!
(2) Adultery debases a person. It makes him resemble the beasts; therefore the adulterer is described like a horse neighing. "Everyone neighed after his neighbor's wife." Jeremiah 5:8. It is worse than brutish; for some creatures which are void of reason—yet by the instinct of nature, observe some decorum and chastity. The turtle-dove is a chaste creature, and keeps to its mate. And the stork, wherever he flies, comes into no nest but his own. Naturalists write that if a stork, leaving his own mate, joins with any other, all the rest of the storks fall upon it, and pull its feathers from it. Adultery is worse than brutish, it degrades a person of his honor.
(3) Adultery pollutes. The devil is called an unclean spirit. Luke 11:24. The adulterer is the devil's first-born; he is unclean; he is a moving quagmire. He is all over ulcerated with sin; his eyes sparkle with lust; his mouth foams out filth; his heart burns like mount Etna, in unclean desires. He is so filthy, that if he dies in this sin, all the flames of hell will never purge away his immorality! And, as for the adulteress, who can paint her black enough? The Scripture calls her a deep ditch. Proverbs 23:27. She is a common sewer! The body of a harlot is a walking dung-hill, and her soul a lesser hell!
(4) Adultery is destructive to the body. "Afterward you will groan in anguish when disease consumes your body." Proverbs 5:11. Immorality turns the body into a hospital, it brings foul diseases, and eats the beauty of the face. As the flame wastes the candle, so the fire of lust consumes the body. The adulterer hastens his own death. "So she seduced him with her pretty speech. With her flattery she enticed him. He followed her at once, like an ox going to the slaughter or like a trapped stag, awaiting the arrow that would pierce its heart. He was like a bird flying into a snare, little knowing it would cost him his life!" Proverbs 7:21-23.
(5.) Adultery is a drain upon the purse; it wastes not the body only—but the estate. "Keeping you from the immoral woman, from the smooth tongue of the wayward wife. Do not lust in your heart after her beauty or let her captivate you with her eyes, for the prostitute reduces you to a loaf of bread, and the adulteress preys upon your very life!" Proverbs 6:24-26. Whores are the devil's horse-leeches, sponges that suck in money. The prodigal son spent his inheritance, when he fell among harlots. Luke 15:30. The concubine of King Edward III, when he was dying, got all she could from him, and even plucked the rings off his fingers.
(6) Adultery destroys reputation. "But the man who commits adultery is an utter fool, for he destroys his own soul. Wounds and constant disgrace are his lot. His shame will never be erased!" Proverbs 6:32, 33. Wounds of reputation—no physician can heal. When the adulterer dies, his shame lives. When his body rots underground, his name rots above ground. His bastard children are living monuments of his shame.
(7) Adultery impairs the mind. It steals away the understanding; it stupefies the heart. "Whoredom and wine take away the heart." Hosea 4:11. It eats all purity out of the heart. Solomon besotted himself with women, and they enticed him to idolatry.
(8) Adultery incurs temporal judgments. The Mosaic law made the penalty for adultery, to be death. "The adulterer and adulteress shall surely be put to death;" and the usual death was stoning. Lev 20:10; Deut. 22:24. The Salons commanded people guilty of this sin, to be burnt. The Romans caused their heads to be stricken off. Like a scorpion—this sin carries a sting in its tail. "For jealousy arouses a husband's fury, and he will show no mercy when he takes revenge!" Proverbs 6:34. The adulterer is often killed in the act of his sin. "Lust's practice is to make a joyful entrance—but she leaves in misery." I have read of two in London, who, having defiled themselves with adultery, were immediately struck dead with lightening from heaven. If all who are now guilty of this sin were to be punished in this manner, it would rain fire again, as on Sodom.
(9) Adultery, without repentance, damns the soul. "Do you not know that the wicked will not inherit the kingdom of God? Do not be deceived: Neither the sexually immoral nor idolaters nor adulterers nor homosexual offenders . . . will inherit the kingdom of God!" 1 Corinthians 6:9-10. The fire of lust, brings to the fire of hell. "God will judge the adulterer and all the sexually immoral!" Hebrews 13:4. Though men may neglect to judge them—yet God will judge them! He will judge them assuredly; they shall not escape the hand of justice; and He will punish them severely. The harlot's breasts keeps from Abraham's bosom! "The delight lasts a moment—the torment an eternity!" Who for a cup of pleasure—would drink a sea of wrath! "Her guests are in the depths of hell." Proverbs 9:18. The harlot is perfumed with powders, and lovely to look on—but poisonous and damnable to the soul! "She has cast down many wounded, yes, many strong men have been slain by her." Proverbs 7:26.
(10) The adulterer does all he can, to destroy the soul of another—and so kills two at once! He is worse than the thief; for, suppose a thief robs a man, yes, and also takes away his life— the man's soul may be happy; he may go to heaven as well as if he had died in his bed. But he who commits adultery, endangers the soul of another, and does all he can, to deprive her of salvation. What a fearful thing it is—to be an instrument to draw another to hell!
(11) The adulterer is abhorred of God. "The mouth of an adulteress is a deep pit; he who is abhorred by the Lord, will fall into it." Proverbs 22:14. What can be worse than to be abhorred by God? God may be angry with His own children; but for God to abhor a man—is the highest degree of hatred! The immoral person stands upon the threshold of hell; and when death gives him a push—he tumbles in!
All this should sound a warning in our ears, and call us off from the pursuit of so damnable a sin as immorality. Hear what the Scriptures say: "Her house is the way to hell." Proverbs 7:27.
I shall give some directions, by way of antidote, to keep from the infection of this sin.
(1) Do not come into the company of a whorish woman; avoid her house, as a seaman does a rock. "Run from her! Don't go near the door of her house!" Proverbs 5:8. He who would not have the plague, must not come near infected houses; every whore-house has the plague in it. Not to avoid the occasion of sin, and yet pray, "Lead us not into temptation," is, as if one should put his finger into the candle, and yet pray that it may not be burnt!
(2) Look to your eyes. Much sin comes in by the eye. "Having eyes full of adultery." 2 Pet 2:14. The eye tempts the imagination, and the imagination works upon the heart. A lustful amorous eye, may usher in sin. Eve first saw the tree of knowledge—and then she took. Gen 3:6. First she looked—and then she loved. The eye often sets the heart on fire; therefore Job laid a law upon his eyes. "I made a covenant with my eyes—not to look with lust upon a young woman." Job 31:1.
(3) Look to your lips. Take heed of any unclean word which may enkindle unclean thoughts in yourselves or others. "Evil communications corrupt good manners." 1 Cor. 15:33. Impure discourse, is the bellows to blow up the fire of lust. Much evil is conveyed to the heart by the tongue. "Set a watch, O Lord, before my mouth!" Psalm 141:3.
(4) Look in a special manner to your heart. "Guard your heart with all diligence." Proverbs 4:23. Every person has a tempter in his own bosom! "Out of the heart proceed evil thoughts, adultery, all other sexual immorality." Matthew 15:19. Thinking of sin, makes way for the act of sin. Suppress the first risings of sin in your heart. As the serpent, when danger is near—guards his head, so keep your heart, which is the spring from whence all lustful motions proceed.
(5) Look to your attire. We read of the attire of a harlot. Proverbs 7:10. A wanton dress is a provocation to lust. A painted face, and half-naked breasts, are allurements to immorality. Where the sign is hung out—people will go in and taste the liquor. Jerome says, "those who by their lascivious attire endeavor to draw others to lust, though no evil follows—are tempters—and shall be punished, because they offered the poison to others, even though they would not drink."
(6) Take heed of evil company. Sin is a very contagious disease; one person tempts another to sin, and hardens him in it. There are three cords which draw men to immorality:
the inclination of the heart,
the persuasion of evil company, and
the embraces of the harlot. This threefold cord is not easily broken. "A fire was kindled in their company." Psalm 106:18. The fire of lust is kindled in bad company.
(7) Beware of going to theaters and plays. A play-house is often a preface to a whorehouse. "Plays furnish the seeds of wickedness." We are bid to avoid all appearance of evil; and are not plays the appearance of evil? Such sights are there, which are not fit to be beheld with chaste eyes. A learned divine observes, that many have on their death-beds confessed, with tears, that the pollution of their bodies has been occasioned by going to plays.
(8) Take heed of mixed dancing. "Dances are instruments of lust and wantonness." From dancing, people come to dalliance with another, and from dalliance to immorality. "There is," says Calvin, "for the most part, some unchaste behavior in dancing." Dances draw the heart to immorality—by wanton gestures, by unchaste touches, and by lustful looks. Chrysostom inveighed against mixed dancing in his time. "We read," he says, "of a marriage feast—but of dancing there—we read not." Matthew 25:7. Many have been ensnared by dancing. "Dancing is not the conduct of a chaste woman—but of the adulteress," says Ambrose. Chrysostom says, "Where dancing is, there the devil is!"
(9) Take heed of lascivious books and pictures, which provoke to lust. As the reading of the Scripture stirs up love to God, so reading vile books stirs up the mind to wickedness. To lascivious books I may add lascivious pictures, which bewitch the eye, and are incendiaries to lust! They secretly convey poison to the heart.
(10) Take heed of excess in diet. When gluttony and drunkenness lead the van, immorality and wantonness bring up the rear. "Wine inflames lust." "Sodom's sins were pride, laziness, and gluttony." Ezekiel 16:49. The foulest weeds grow out of the fattest soil. Immorality proceeds from excess. "When I had fed them to the full, everyone neighed after his neighbor's wife." Jer. 5:8. Get the "golden bridle of temperance." God allows the refreshment of nature, and what may fit us the better for his service; but beware of surfeit. Excess in temporal things—clouds the mind, chokes good affections, and provokes lust. "I discipline my body and bring it under strict control." 1 Cor. 9:27. The flesh pampered—is liable to immorality.
(11) Take heed of idleness. When a man is idle, he is ready to receive any temptation. The devil sows most of his seeds of temptation in fallow ground. Idleness is the cause of sodomy and immorality. "Sodom's sins were pride, laziness, and gluttony." Ezekiel 16:49. When David was idle on the top of his house, he espied Bathsheba, and committed adultery with her. 2 Samuel 11:4. Jerome gave his friend counsel to be always well employed in God's vineyard, that when the devil came, he might have no leisure to listen to temptation.
(12) To avoid fornication and adultery, let every man have a chaste, entire love to his own wife. Ezekiel's wife was the desire of his eyes. Ezekiel 24:16. When Solomon had dissuaded from immoral women, he prescribed a remedy against it. "Rejoice with the wife of your youth." Proverbs 5:18. It is not having a wife—but loving a wife— which makes a man live chastely. He who loves his wife, whom Solomon calls his fountain, will not go abroad to drink of muddy, poisoned waters. Pure marital love is a gift of God, and comes from heaven; but, like the vestal fire, it must be nourished, so that it does not go out. He who does not love his wife, is the likeliest person to embrace the bosom of a harlot.
(13) Labor to get the fear of God into your hearts. "By the fear of the Lord, men depart from evil." Proverbs 16:6. As the embankment keeps out the water, so the fear of the Lord keeps out immorality. Such as lack the fear of God, lack the bridle which should check them from sin! How did Joseph keep from his mistress' temptation? The fear of God pulled him back! "How can I do this great wickedness, and sin against God!" Genesis 39:9. Bernard calls holy fear, "the door-keeper of the soul." As a nobleman's porter stands at the door, and keeps out vagrants, so the fear of God stands and keeps out all sinful temptations from entering.
(14) Take delight in the Word of God. "How sweet are your words unto my taste." Psalm 119:103. Chrysostom compares God's Word to a garden. If we walk in this garden, and suck sweetness from the flowers of the promises, we shall never care to pluck the "forbidden fruit." "Let the Scriptures be my pure pleasure," says Augustine. The reason why people seek after unchaste, sinful pleasures—is because they have nothing better. Caesar riding through a city, and seeing the women play with dogs and parrots, said, "Surely, they have no children." So those who sport with harlots, have no better pleasures. He who has once tasted Christ in a promise, is ravished with delight; and he would scorn a temptation to sin! Job said, that the Word was his "appointed food." Job 23:12. No wonder then, that he made a "covenant with his eyes."
(15) If you would abstain from adultery, use serious consideration.
 Consider that God sees you in the act of sin! He sees all your curtain wickedness. He is totus oculus—"all eye." The clouds are no canopy, the night is no curtain—to hide you from God's eye! Whenever you sin—your Judge looks on! "I have seen your detestable acts—your adulteries and your neighings." Jer. 13:27. "They have committed adultery with their neighbors' wives. I know it and am a witness to it! declares the Lord." Jer. 29:23.
 Consider that few who are entangled in the sin of adultery, ever recover from the snare. "None that go to her return again." Proverbs 2:19. This made some of the ancients conclude that adultery was an unpardonable sin; but it is not so. David repented. Mary Magdalene was a weeping penitent; upon her amorous eyes which sparkled with lust, she sought to be revenged, by washing Christ's feet with her tears! Some, therefore have recovered from this snare. "None that go to her return," that is, "very few." It is rare to hear of any who are enchanted and bewitched with the sin of immorality, who recover from it. "I find more bitter than death the woman who is a snare, whose heart is a trap and whose hands are chains. The man who pleases God will escape her, but the sinner she will ensnare." Eccl. 7:26. Her "heart is a trap," that is, she is subtle to deceive those who come to her; and "her hands are chains," that is her embraces are powerful to hold and entangle her lovers. This consideration should make all fearful of this sin. Soft pleasures, harden the heart.
 Consider what Scripture says, which may lay a barricade in the way to this sin. "I will be a swift witness against the adulterers." Malachi 3:5. It is good when God is a witness "for us", when He witnesses to our sincerity, as He did to Job's; but it is sad to have God as a "witness against us." "I," says God, "will be a swift witness against the adulterer." And who shall disprove God's witness? He is both witness and judge! "God will surely judge people who are immoral and those who commit adultery." Hebrews 13:4.
 Consider the sad farewell, which the sin of adultery leaves. It leaves a hell in the conscience. "The lips of an immoral woman are as sweet as honey, and her mouth is smoother than oil. But the result is as bitter as poison, sharp as a double-edged sword. Her feet go down to death; her steps lead straight to hell." Proverbs 5:3-5. The goddess Diana was so artfully drawn, that she seemed to smile upon those who came into her temple—but frown on those who went out. So the harlot smiles on her lovers as they come to her—but at last, they come to the frown and the sting! "Until an arrow pierces his liver." Proverbs 7:23. "Her end is bitter."
When a man has been virtuous, the labor is gone—but the comfort remains; but when he has been wicked and immoral, the pleasure is gone—but the sting remains. "He gains momentary pleasure—but after that, eternal torment," says Jerome. When the senses have been feasted with unchaste pleasures, the soul is left to pay the reckoning. Stolen waters are sweet; but, as poison, though sweet in the mouth, it torments the conscience. Sin always ends in tragedy! Sad is that which Fincelius reports of a priest in Flanders, who enticed a young girl to immorality. When she objected how vile a sin it was, he told her that by authority from the Pope, he could commit any sin; so at last he drew her to his wicked purpose. But when they had been together a while, in came the devil, and took away the harlot from the priest's side, and, notwithstanding all her crying out, carried her away! If the devil should come and carry away all who are guilty of immorality in this nation—I fear more would be carried away, than would be left behind!
(16) Pray against this sin. Luther gave a lady this advice, that when any lust began to rise in her heart, she should go to prayer. Prayer is the best armor against sin; it quenches the wild fire of lust. If prayer will "cast out the devil," it will certainly cast out those lusts which come from the devil.
O let us labor for soul purity! To keep the soul pure—have recourse to the blood of Christ, which is the "fountain open, to cleanse from sin and impurity." Zech. 13:1. A soul steeped in the briny tears of repentance, and bathed in the blood of Christ—is made pure! Say, "Lord, my soul is defiled! I pollute all I touch! O purge me with hyssop—let Christ's blood sprinkle me, let the Holy Spirit anoint me. O make me pure, that I may be taken to heaven—where I shall be as holy as You would have me to be—and as happy as I can desire to be!"