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. This is a synec-doche: [1] for not only the eyes, but even the concealed flames of the heart, render men guilty of adultery. Accordingly, Paul makes chastity (1-Corinthians 7:34) to consist both in body and in mind. But Christ reckoned it enough to refute the gross mistake which was prevalent: for they thought that it was only necessary to guard against outward adultery. As it is generally by the wantonness of the eyes that temptations are presented to the mind, and as lust enters, as it were, by that door, Christ used this mode of speaking, when he wished to condemn lust: which is evident from the expression, to lust after her. This teaches us also, that not only those who form a deliberate purpose of fornication, but those who admit any polluted thoughts, are reckoned adulterers before God. The hypocrisy of the Papists, therefore, is too gross and stupid, when they affirm that lust is not a sin, until it gain the full consent of the heart. But we need not wonder, that they make sin to be so small a matter: for those who ascribe righteousness to the merit of works must be very dull and stupid in judging of their sins.

Footnotes

1 - "C'est une facon de parler qu'on appelle Synecdoche, quand on prend une artie our le tout." -- "It is a way of speaking which is called Synecdoche, when a part is taken for the whole."

Whosoever looketh on a woman to lust after her - Επιθυμησαι αυτην, earnestly to covet her. The verb, επιθυμεω, is undoubtedly used here by our Lord, in the sense of coveting through the influence of impure desire. The word is used in precisely the same sense, on the same subject, by Herodotus, book the first, near the end. I will give the passage, but I dare not translate it. To the learned reader it will justify my translation, and the unlearned must take my word. Της ΕΠΙΘΥΜΗΣΕΙ γυναικος Μασσαγετης ανηρ, μισγεται αδεως, Raphelius, on this verse, says, επιθυμειν hoc loco, est turpi cupiditate mulieris potiundae flagrare. In all these eases, our blessed Lord points out the spirituality of the law; which was a matter to which the Jews paid very little attention. Indeed it is the property of a Pharisee to abstain only from the outward crime. Men are very often less inquisitive to know how far the will of God extends, that they may please him in performing it, than they are to know how far they may satisfy their lusts without destroying their bodies and souls, utterly, by an open violation of his law.
Hath committed adultery with her already in his heart - It is the earnest wish or desire of the soul, which, in a variety of cases, constitutes the good or evil of an act. If a man earnestly wish to commit an evil, but cannot, because God puts time, place, and opportunity out of his power, he is fully chargeable with the iniquity of the act, by that God who searches and judges the heart. So, if a man earnestly wish to do some kindness, which it is out of his power to perform, the act is considered as his; because God, in this case, as in that above, takes the will for the deed. If voluntary and deliberate looks and desires make adulterers and adulteresses, how many persons are there whose whole life is one continued crime! whose eyes being full of adultery, they cannot cease from sin, 2-Peter 2:14. Many would abhor to commit one external act before the eyes of men, in a temple of stone; and yet they are not afraid to commit a multitude of such acts in the temple of their hearts, and in the sight of God!

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 on a woman's little finger, and say (m), that he that tells money to a woman, out of his hand into her's, that he may look upon her, though he is possessed of the law and good works, even as Moses, he shall not escape the damnation of hell: they affirm (n), that he that looks upon a woman's heel, his children shall not be virtuous; and that a man may not go after a woman in the way, no, not after his wife: should he meet her on a bridge, he must take her to the side of him; and whoever goes through a river after a woman, shall have no part in the world to (o) come: nay, they forbid (p) a man looking on the beauty of his own wife. Now these things were said by them, chiefly to cover themselves, and because they would be thought to be very chaste; when they were, as Christ calls them, an "adulterous generation" in a literal sense: they usually did what our Lord observes, "strain at a gnat, and swallow a camel". We read in the Talmud (q), of , a "foolish saint" and it is asked, who is he? and it is answered, one that sees a woman drowning in a river, and says it is not lawful for me , "to look" upon her, and deliver her. It was not any looking upon a woman, that is forbid by Christ as criminal; but so to look, as "to lust after her"; for such an one
hath committed adultery with her already in his heart. But these men, who forbad external looking upon a woman, generally speaking, had no notion of heart sins; and which was the prevailing opinion of the Pharisees, in Christ's time.
"A good thought, they (r) allow, is reckoned as if done; as it is said, Malachi 3:16. Upon which it is asked, what is the meaning of that, and "that thought" upon "his name?" Says R. Ase, if a man thinks to do a good work, and is hindered, and does it not, the Scripture reckons it to him, as if he did it; but an evil thought, the holy blessed God does not account of it as if done, as is said, Psalm 66:18.''
Upon which words, a noted commentator (s) of their's has this remark:
"Though I regard iniquity in my heart to do it, even in thought, yea, against God himself, as if I had expressed it with my lips, he does not hear it; that is, , "he does not reckon it to me for sin"; because the holy blessed God does not account an evil thought for an action, to them that are in the faith of God, or of the true religion.''
For it seems, this is only true of the Israelites; it is just the reverse with the Gentiles, in whom God does not reckon of a good thought, as if it was done, but does of an evil one, as if it was in act (t). It must be owned, that this is not the sense of them all; for some of them have gone so far as to say (u), that
"the thoughts of sin are greater, or harder, than sin itself:''
by which they mean, that it is more difficult to subdue sinful lusts, than to refrain from the act of sin itself; and particularly, some of them say things which agree with, and come very near to what our Lord here says; as when they affirm (w), that
"everyone that looks upon a woman with intention, it is all one as if he lay with her.''
And that , "he that committeth adultery with his eyes, is called an adulterer" (x). Yea, they also observe (y), that a woman may commit adultery in her heart, as well as a man; but the Pharisees of Christ's time were of another mind.
(k) T. Bab. Avoda Zara, fol. 1, 2. (l) T. Bab. Beracot, fol. 24. 1. Sabbat. fol. 64. 2. (m) T. Bab. Beracot, fol. 61. 1. Eruvin, fol. 18. 2. (n) T. Bab. Nedarim, fol. 20. 1. T. Hieros. Challa, fol. 58. 3. Derech Eretz. c. 1. fol. 17. 3. (o) T. Bab. Beracot, fol. 61. 1. Eruvin, fol. 18. 2. (p) Zohar in Leviticus. fol. 34. 4. (q) T. Bab Sota, fol. 21. 2. (r) T. Bab. Kiddushin, fol. 40. 1. (s) R. David Kimchi, in Psal. lxvi. 18. (t) T. Hieros. Peah, fol. 16. 2. (u) T. Bab. Yoma, fol. 29. 1. (w) T. Hieros. Challa, fol. 58. 3. Massechet Calah, fol. 16. 4. Vid. Maimon. Issure Bia, c. 21. sect. 2. & Moses Kotsensis Mitzvot Tora precept. neg. 126. (x) Vajikra Rabba, sect. 23. fol. 265. 1. (y) Bemidbar Rabba, sect. 9. fol. 196. 1.

But I say unto you, That whosoever looketh on a woman to lust after her--with the intent to do so, as the same expression is used in Matthew 6:1; or, with the full consent of his will, to feed thereby his unholy desires.
hath committed adultery with her already in his heart--We are not to suppose, from the word here used--"adultery"--that our Lord means to restrict the breach of this commandment to married persons, or to criminal intercourse with such. The expressions, "whosoever looketh," and "looketh upon a woman," seem clearly to extend the range of this commandment to all forms of impurity, and the counsels which follow--as they most certainly were intended for all, whether married or unmarried--seem to confirm this. As in dealing with the sixth commandment our Lord first expounds it, and then in the four following verses applies His exposition (Matthew 5:21-25), so here He first expounds the seventh commandment, and then in the four following verses applies His exposition (Matthew 5:28-32).