What is the significance of Jesus repeating "but I say to you" in Matthew 5?

The Lord Jesus now sets His own words over against this commandment with its human addition: "But I say unto you." These words occur five times in this part of the fifth chapter. He speaks with the same authority as the One who had once given the law, for He is the Son of God. Yet He does not set aside the law by His words but extends its application to man's condition of heart. Whilst the commandment only forbade the extreme manifestation of hatred, i.e. killing a person, the Lord shows that anger with a brother (which means the Jewish "brother" here) deserves the same punishment as killing itself.

If in the opinion of the Rabbis only the murderer was subject to this judgment, the Lord's words show that the one who was angry with his brother for no reason was subject to the same judgment. The one who called his brother "Raca" (Aramaic: "reka"-fool, lunatic) was subject to be called before the Sanhedrin (the supreme Jewish court at that time), and whosoever should say "fool" was to be subject to hell ("Gehenna"): eternal damnation. If the last of these three sins, which hardly differ from one another, led to eternal damnation, then the others would do so as well. God does not look at the outward appearance but into our hearts.

The Lord Jesus now sets His own words over against this commandment with its human addition: “But I say unto you.” These words occur five times in this part of the fifth chapter. He speaks with the same authority as the One who had once given the law, for He is the Son of God. Yet He does not set aside the law by His words but extends its application to man's condition of heart. Whilst the commandment only forbade the extreme manifestation of hatred, i.e. killing a person, the Lord shows that anger with a brother (which means the Jewish “brother” here) deserves the same punishment as killing itself.

If in the opinion of the Rabbis only the murderer was subject to this judgment, the Lord's words show that the one who was angry with his brother for no reason was subject to the same judgment. The one who called his brother “Raca” (Aramaic: “reka” — fool, lunatic) was subject to be called before the Sanhedrin (the supreme Jewish court at that time), and whosoever should say “fool” was to be subject to hell (“Gehenna”): eternal damnation. If the last of these three sins, which hardly differ from one another, led to eternal damnation, then the others would do so as well. God does not look at the outward appearance but into our hearts.

Eight times over does He say in this chapter, "I say to you," and on six of these occasions the words are preceded by the word, "But," throwing His statement into contrast with what the law had previously said. We may well ask, "Who is this that quotes the holy law of God, and then calmly says, "But I say to you" — so and so? He actually alters and enlarges the law, a thing that no prophet had ever dared to do! Does this not amount to terrible presumption, bordering on blasphemy?" Yes, indeed, and only one explanation will lift this charge from off Him. But that one explanation is true: here we have the original Lawgiver, who once spoke from Sinai. Now He has come forth in Manhood as Emmanuel. Emmanuel has gone up another mountain, and now speaks not to a nation but to His disciples. He has every right to enlarge or amend His own law.

HAVING INTRODUCED His disciples to God in this new light at the end of Matt. 5, we notice that all the teaching in Matt. 6 is in reference to it. The expression "your Father," in slightly varying terms, occurs no less than twelve times. The teaching falls into four sections: almsgiving (1-4), prayer (5-15), fasting (16-18), earthly possessions and the necessary things of life (19-34). All four things touched the practical life of the Jew at many points, and their tendency and habit was to take up the first three in a technical, perfunctory way, and to lay all the stress and pay all the attention to item number four. The Lord Jesus sets them all in the light which His earlier words had shed. In chapter 5. He had shown them a God who deals with the inward motions of the heart as much as with outward actions, and yet that God is to be known as a heavenly Father. Still we notice how He repeats, "I say to you." He does not teach as did the scribes, basing their assertions on the traditions of the ancients, but we have to take what He says, just because He says it.

Next He goes farther, not merely "for verily I say to you" (18) and "for I say to you" (20) but with all the emphasis of superior divine light, worthy of God's Son, "Ye heard that it was said to the ancients, Thou shalt not kill … But I say to you" (21-26), and "ye heard that it was said, Thou shalt not commit adultery. But I say to you" (27-30); and incomparably more searching commandments are applied to the law's prohibition of violence and corruption only in their extreme forms.

The Scribes and Pharisees were especially ritualist and external. This was letter, not spirit. Our Lord not only condemns a righteousness of mere outward acts, but insists on inward reality as indispensable for the kingdom of the heavens. He does not explain at this time how the requisite practical righteousness is possible and actually made good in sinful men. He had already let Nicodemus know of the necessity for a Jew no less than a Greek to be born anew, as well as to have redemption by His cross. Here to His disciples He expounds the absolute need of realising the varied spiritual qualities brought before them in order to enter the kingdom. As the Pharisees fatally narrowed the scope of scripture, the Lord gave its fulness as none but He could. The first of these references is to the law of murder. But the Lord goes immeasurably farther for the kingdom.

"Ye have heard that it was said to those of old, Thou shalt not kill; and whosoever shall kill shall be subject to the judgment. But I say to you, that everyone that is [rightly] angry with his brother shall be subject to the judgment; whosoever shall say to his brother, Raca, shall be subject to the council; and whosoever shall say, Fool, shall be subject to the hell of fire" (Matt. 5:21-22). The law and the prophets He had vindicated. All must come to pass. Yet the law made nothing perfect. He speaks Who is above the law and gave fulness to all on His own authority.

Thus is the commandment made exceeding broad and deep. The axe is laid to the root of the evil tree. All violent feelings are judged as in God's sight, and every evil word of malice and contempt shown to be of sinful and dangerous consequence. As He said later in the same Gospel (Matt. 12:37), "By thy words thou shalt be justified, and by thy words thou shalt be condemned." Here He warns, not so much of every light word, but of wrath, hatred, and contempt. The Judge of all the earth, Himself despised by man and abhorred by the nation, as was soon proved, could not fail to discern aright.

The prophets of old had come before the people with "Thus says the Lord" on their lips, for in times past, and in divers manners, God spoke to the fathers thus: but in the Sermon on the Mount Jesus stood forth and said, "I SAY UNTO YOU," and those who heard Him were astonished at His doctrine, for He taught them as One having authority (Luke 7:29). This authority was the authority of the Lord, for this He declares Himself to be, having power to exclude from the kingdom of heaven all those who do not do the will of His Father which is in heaven. See how intimately He connects the kingdom of heaven with Himself. Some whose lips had owned Him, but whose hearts had not yielded to His Father's will, will desire to enter that kingdom: He will say to them, "Depart from ME": and He will say this, as being able to look behind the profession and all that is external, and read the heart, which none but God can do (Luke 7:21).

The prophets of old had come before the people with "Thus says the Lord" on their lips, for in times past and in diverse manners God spoke to the fathers thus; but in the Sermon on the Mount Jesus stood forth and said, "I SAY UNTO YOU," and those who heard Him were astonished at His doctrine, for He taught them AS HAVING AUTHORITY (chap. 7:28). This authority was the authority of the Lord, for this He declares Himself to be, having power to exclude from the kingdom of heaven all those who do not do the will of His Father which is in heaven. See how intimately He connects the kingdom of heaven with Himself. Some whose lips had owned Him, but whose hearts had not yielded to His Father's will, will desire to enter that kingdom; He will say to them, "Depart from ME"; and He will say this, as being able to look behind the profession and all that is external, and read the heart, which none but God can do (chap. 7:21).

In the going up the mountain, as we have in the beginning of Matt. 5, we have a parallel with Moses when he went up mount Sinai to receive the law from God to pass on to the children of Israel, both the tables of testimony and the ceremonial ordinances connected with them. So here we see our Lord sitting at the top of the mountain with His disciples gathered around Him, enunciating the principles of the kingdom of heaven. We have here what we may call the statute book of the kingdom. It is the King stating the principles of His kingdom which, as we have said, would be established if they would receive it by receiving Him. As we know, this co-called sermon on the mount runs on to the end of Matt. 7, and in the compass of these verses we hear our Lord saying, "Ye have heard that it was said" (Matt. 5:21), "but I say unto you." Fourteen times we hear the Lord saying, "I say." Who but One Who was God dare speak in this way? In the authority of His Own Person, yet in His position as the Messiah, He opens out these new principles.

Clearly it is not the law of Moses, and yet in those chapters we hear the voice of the original Law-giver, setting before us, as has well been said, "not a new code but a new edition of the old one," "clearing up His own intentions and disallowing the perversions of men." This is particularly marked in Matt. 5:17 to 48. He announces Himself as the One come not to destroy the law, but to fulfil, or give the fulness of it. Hence the repeated words, "Ye have heard that it was said … But I say to you …" Note Matt. 5:20, 22, 26, 28, 82, 84, 89, 44, and Matt. 6:2, 5, 16, 25, and 29.

The conclusion of the incident shows that, in result, the religious leaders who came to the Lord to convict Him as a Teacher of the people were themselves convicted by Him. It affords an instance, in accordance with the special purpose of Mark's narrative, of the absolute perfection of the Servant of Jehovah, in that He used the written word of God as the instrument of conviction, rather than His own personal authority. Matthew, setting out the King of the Jews come to adminster the kingdom of the heavens according to the law and the prophets, records the same instance (Matt. 15). When, therefore, the Lord spoke as the Prophet like unto Moses, and brought out of His treasure-house "things new," His utterances were in His own authority, and not like those of the scribes of the day. On such occasions He taught after this manner: "Ye have heard that it was said to them of old time … but I say unto you… ." At such times He was depositing with the people the word of Him who sent Him — a word which in the course of the progress of Divine revelation was given to supplement and to amplify the communications of old. But when the Lord opposed the false teachers of Israel His appeal was to the Scriptures. To their confusion He confronted them with what was on record and what was read by them on sabbath days in their synagogues. The proud Pharisees then found themselves in the presence of the One out of whose mouth went a sharp sword, and for their condemnation, as it were, the books were opened, and they were judged out of the things written in the books.