What does the Lord Jesus Christ teach regarding adultery?
Our Lord Jesus Christ reveals the full extent of this commandment:
You have heard that it was said, ‘You shall not commit adultery.’ But I say to you: everyone who looks at a woman with lust for her has already committed adultery with her in his heart. If your right eye causes you to stumble, tear it out and throw it from you: for it is better for you to lose one of your members than for your whole body to be thrown into Gehenna. (Mat 5:27–30)
From this, we see that the Law of God is not merely a code inscribed on tablets of stone but is to be received in the heart as precious and life-giving (Jer 31:31–33; see Q030, Q043). Already in the second century, the Christian apologists could point to this interior chastity as the mark of the Church: “Who among your philosophers is pure? But among us you will find common folk, artisans, and old women who… exhibit the truth in deeds. For we are not concerned with words but with works: ‘whoever looks upon a woman to lust after her has already committed adultery in his heart’, so that to us even a lustful look is forbidden” (Athenagoras of Athens, Plea for the Christians 11, 32 [c. 177]).
