The Christian is to proclaim and prosecute an irreconcilable war against his bosom sins;those sins which have lain nearest his heart, must now be trampled under his feet. So David, ‘I have kept myself from my iniquity.’ Now what courage and resolution does this require? You think Abraham was tried to purpose, when called to take his ‘son, his son Isaac, his only son whom he loved,’ Gen. 22:2, and offer him up with his own hands, and no other; yet what was that to this?
Soul, take thy lust, thy only lust, which is the child of thy dearest love, thy Isaac, the sin which has caused the most joy and laughter, from which thou hast promised thyself the greatest return of pleasure or profit; as ever thou lookest to see my face with comfort, lay hands on it and offer it up: pour out the blood of it before me; run the sacrificing knife of mortification into the very heart of it; and this freely, joyfully, for it is no pleasing sacrifice that is offered with a countenance cast down —and all this now, before thou hast one embrace more from it.
Truly this is a hard chapter, flesh and blood cannot bear this saying; our lust will not lie so patiently on the altar, as Isaac, or as a ‘Lamb that is brought to the slaughter which was dumb,’ but will roar and shriek; yea, even shake and rend the heart with its hideous outcries.
Who is able to express the conflicts, the wrestlings, the convulsions of spirit the Christian feels, before he can bring his heart to this work? Or who can fully set forth the art, the rhetorical insinuations, with which such a lust will plead for itself? One while Satan will extenuate and mince the matter: It is but a little one, O spare it, and thy soul shall live for all that.
Another while he flatters the soul with the secrecy of it: Thou mayest keep me and thy credit also; I will not be seen abroad in thy company to shame thee among thy neighbours; shut me up in the most retired room thou hast in thy heart, from the hearing of others, if thou wilt only let me now and then have the wanton embraces of thy thoughts and affections in secret.
If that cannot be granted, then Satan will seem only to desire execution may be stayed awhile, as Jephthah’s daughter of her father: ‘let me alone a month or two, and then do to me according to that which hath proceeded out of thy mouth,’ Judges 11:36, 37, well knowing few such reprieved lusts but at last obtain their full pardon; yea, recover their favour with the soul. Now what resolution doth it require to break through such violence and importunity, and notwithstanding all this to do present execution?
Here the valiant swordsmen of the world have showed themselves mere cowards, who have come out of the field with victorious banners, and then lived, yea, died slaves to a base lust at home. As one could say of a great Roman captain who, as he rode in his triumphant chariot through Rome, had his eye never off a courtesan that walked along the street: Behold, how this goodly captain, that had conquered such potent armies, is himself conquered by one silly woman.
William Gurnall, The Christian in Complete Armor, Chapter 1, The First Branch