He begins with the crime which the natural conscience most strongly and instinctively condemns, the crime of murder; and shows that the scribes and Pharisees, and those who had been like them in bygone days, really destroyed the sixth commandment by limiting its range to the muscles, so that, if there were no actual killing, the commandment was not broken; whereas its true sphere was the heart, the essence of the forbidden crime being found in unjustifiable anger, even though no word is uttered or muscle moved,--a view of the case which ought to have been suggested to the intelligent student of the law by such words as these: "Thou shalt not hate thy brother in thine heart" (Lev. xix. 17); or again: "Whoso killeth his neighbour ignorantly, whom he hated not in time past, ... is not worthy of death, inasmuch as he hated him not in time past" (Deut. xix. 4). Hatred in the heart, then, is murder. How searching! And how terribly severe the sentence! Even in its least aggravated form it is the same as that decreed against the actual shedding of blood. All the three sentences are death-penalties, only there are aggravations in the penalty where there are aggravations in the offence. Such is the Saviour's teaching on the great subject of sin. Yet there are those who imagine that the Sermon on the Mount is all the gospel they need!
The two practical applications which follow press the searching subject home. The one has reference to the Throne of Grace, and teaches that all offences against a brother must be put away before approaching it. The other has reference to the Throne of Judgment, and teaches by a familiar illustration drawn from common experience in the courts of Palestine that it is an awful thing to think of standing there with the memory of a single angry feeling that had not been forgiven and utterly removed (v. 26).
The crime of adultery furnishes the next illustration; and He deals with it on the same lofty principles and with the same terrible severity. He shows that this crime, too, is of the heart--that even a wanton look is a commission of it; and again follows up His searching exposition by a twofold practical application, first showing that personal purity must be maintained at any cost (vv. 29, 30), and then guarding the sacredness of home, by that exaltation of the marriage bond which has secured the emancipation of woman and her elevation to her proper sphere, and kept in check those frightful evils which are ever threatening to defile the pure and sacred spring from which society derives its life and sustenance (vv. 31, 32).