But I tell you that anyone who looks at a woman to lust after her has already committed adultery with her in his heart.
28. Whoever shall look upon a woman. The design of Christ was to condemn generally the lust of the flesh. He says, that not only those who have seduced their neighbors’ wives, but those who have polluted their eyes by an immodest look, are adulterers before God.
We have here an exposition of the seventh commandment, given us by the same hand that made the law, and therefore was fittest to be the interpreter of it: it is the law against uncleanness, which fitly follows upon the former; that laid a restraint upon sinful passions, this upon sinful appetites, both which ought always to be under the government of reason and conscience...
Commenting on Matthew 5:27-32
But I say unto you, that whosoever looketh on a woman,.... Many and severe are the prohibitions of the Jews, concerning looking upon a woman, which they aggravate as a very great sin: they say (k), it is not lawful to look upon a beautiful woman, though unmarried; nor upon another man's wife, though deformed; nor upon a woman's coloured garments: they forbid (l) looking...