(Synoptics: Matthew 5:27-30) This is the second contrast between true godliness and the so-called godliness, or tradition, of the Rabbis. We must be clear that Christ is not in any way contradicting the law of the Old Testament; he specifically says so.
The believer and the unbeliever have two quite different approaches to the commandments of God. The unbeliever, if he has any sense of God at all, is trying to minimise them. In order to ease his conscience, he is interpreting them in the narrowest possible way, in the hope that he will excuse himself. He sees the commandment as a technicality which must be dealt with. He lets it apply perhaps to that part of him which men can see, but not the part which only God can see. The keeping of it may bring him honour before men if he moves in a certain circle, but he does not seriously think about how the Lord sees him. He is trying to keep his distance from God. But the believer wants to draw near to God. He cannot do this unless he thinks as the Lord thinks and sees things as the Lord sees them. Therefore he studies the commandment and let it speaks to every part of his being. He wants to please the Lord and so he enquires diligently whether he has done enough to please the Lord.
The commandment not to commit adultery includes all lesser sins such as, flirting with the opposite sex, treading on the borders of unfaithful behaviour by using risky language, inappropriate sharing of private matters which should be shared only between husband and wife, reading of lewd literature, watching of sexually explicit films, viewing pornography, inappropriate sexual imagination. The Bible distinguishes between adultery – the sin of unfaithfulness to husband or wife; and the sin of fornication – sexual intercourse outside of marriage. But the seventh commandment includes both of these and all other sexual sins as well.