Matthew 5:27-28,  adultery in your heart

5:27 “You have heard that it was said, ‘You shall not commit adultery;’
5:28 but I tell you that everyone who gazes at a woman to lust after her has committed adultery with her already in his heart.”

(Matt 5:27-28 WEB)

The lustful gaze

Jesus quotes the seventh of the Ten Commandments, then promptly emphasises how God judges intentions rather than deeds. Before you can desire a car, you must already have some idea what it would be like to drive it (however unreal that idea might turn out to be). Before you desire a meal, you first anticipate its taste. The same applies to sexual relations with a person, so, when that person is another’s spouse, a mental act of adultery precedes the desire for any physical action. Hence, although circumstances might never permit a physical consummation, the mind rehearsing the act is every bit as offensive to God. Jesus had chosen an ideal text for making such a point, for, in the case of adultery, such errant thought was already condemned in the tenth commandment, but under the alternate guise of coveting your neighbour’s wife. 

In these verses, Jesus is just expounding fairly standard Jewish teaching, but these were truths that must have made his disciples feel really uncomfortable. His purpose was to remind them that people will always fall short of God’s high expectations and, for a group of young men, what better way to do that. He is talking about sexual sin, but the same principal applied across the board, for he has already explained that hatred is as bad as murder (Matt 5:21-22) and he will go on to talk about coveting what others have (Matt 6:19-7:11). Our thoughts betray us so that everyone gets it wrong, sooner or later.

The language used in Matt 5:27-28 echoes that of Prov 6:23-25, an ancient wisdom teaching, which sees following God’s commandments as the way to avoid the pitfall of attraction to a wayward spouse. The same text entreats its reader not to lust after an adulterous woman and thereby become captivated by her. Jesus wants his audience to understand that such thoughts become the trigger for a supremely subtle trap, for he is about to tell them how, in the likely event that they become ensnared, they can escape.

Whilst the seventh commandment referred explicitly to sexual activity that compromised the trust involved in marriage, Judaism had come to understand adultery in a broader sense. In the Hebrew Bible, God frequently used marriage as a metaphor for his relationship with his people, who, being the bride of God, were expected to reserve their gaze for him alone. Hence, when various prophets were called to criticise God’s people for lusting after foreign nations (e.g. Jer 13:27, Ezek 23:12), that activity was condemned in the same terms as the ‘adultery’ with foreign gods to which it later led. One such a passage, which shows linguistic links to these verses in Matthew, is Ezekiel 23, in which God’s people are criticised in uncompromising terms, not only for lusting after the glamour of the Chaldeans, but by implication also their idolatrous lifestyle. When speaking of adultery, this secondary association would never have been far from the mind of those involved in first-century Judaism, and Jesus would go on to apply this in Matt 5:31-33.

Matt 5:27-28 in detail.