What is the difference between "you shall not murder" and "you shall not kill"?

The sixth commandment, "You shall not murder," must be considered from the viewpoint God intends (v.17). Israel had already killed many enemies that God had told them to, and in the land of Canaan would be required to kill the inhabitants. God commanded this because the inhabitants were given up to idol worship. Similarly, when justice demands the death of a criminal, it is not murder for the authorities to put him to death. But no individual is at liberty to kill another as he sees fit. As we have seen before, Scripture makes a distinction between murder and manslaughter (ch.4:41-42).

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.

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.

The words φονεύς, ἀνθρωποκτόνος, and σικάριος are all translated 'murderer.' φονεύω, the kindred verb to φονεύς (from φόνος, 'murder') is employed in the LXX in the commandment "Thou shalt not kill," and is repeated in the N.T. This shows that it embraces 'murder' in general, and those guilty of it are 'murderers,' Matt. 22:7; 1 Peter 4:15. Barabbas was a murderer, and the people of Israel were the murderers of Jesus. Acts 3:14; Acts 7:52; Acts 28:4.

ἀνθρωποκτόνος (from ἄνθρωπος, 'man,' and κτείνω, 'to slay' agrees more with our word 'man-slayer,' and is applied when murder may not have been committed. "Whosoever hateth his brother is a murderer: and ye know that no murderer hath eternal life abiding in him." 1 John 3:15. The devil "was a murderer [mansleer, Wickliffe] from the beginning." John 8:44. This word serves to bring into contrast the slaying of MAN, and eternal life for man through our Lord Jesus Christ.

The "judgment," the "council" (or Sanhedrin), and the "hell (Gehenna) of fire" are three grades of penalty, as is evident; but in the Kingdom of heaven all under one authority. "Thou shalt not kill" stood as the sixth commandment of the law. God had long before declared that "whoso sheddeth man's blood, by man shall his blood be shed." The executive law in Israel could go no further than this. It could not deal with the state of the heart but with the outward act only. But the law as expressed on the tables of stone applied not merely to the outward act, and their appending in the way they did the executive to the moral law, inferred that the two were equal in what they covered; as they were not. The state of the heart was thus left out of view in the estimate of accountability toward God, and the practical bearing of the law was nullified for the many.

Cain was a murderer, and the murderous hatred of his brother was in his heart before he actually slew him. So it was with the leaders of Israel who, with wicked hands, crucified and slew the Son of God. Jesus convicted them of their hatred to Him before they actually slew Him. Every one with hatred in his heart towards a Christian, because he is a Christian, is viewed by God as a murderer. God can and does look into the heart, and judges the motives and feelings of the heart; and where there is the hatred of the one who manifests the divine life, God calls it murder.

The second (2 1-26) begins the expansion of it with that of the commandment, "Thou shalt not kill;" forbidding the enmity of the heart in its least outflow, and establishing the law itself as the adversary to be reconciled by one against whom his brother thus has ought.

He takes some of the commandments which He wrote on the second table of stone and begins with the commandment: "Thou shalt not kill." Murder was the first awful fruit after the fall, sprung as it was from envy in the heart. The penalty of murder is the judgment. This, then, is the letter of the law. It dealt with the outward deed, but the heart itself it did not touch. Now He speaks. "I say unto you, that every one that is _lightly angry with his brother shall be subject to the judgment." (The word "lightly" belongs in here. It was dropped in some manuscripts, but stands in the oldest. It is not angry alone outwardly, but even the remotest feeling of displeasure is meant.) It shall be as if he had committed the deed "thou shalt not kill." Every one that hates his brother is a murderer (1 John 3:15). "Whosoever shall say to his brother, Raca (a word embodying hatred and contempt) shall be called before the Sanhedrin; but whosoever shall say, Fool, shall be subject to the penalty of the hell fire." It will be so, no doubt, when the kingdom will be come into the earth; swift judgment will overtake the offender. But the words lay bare the heart and show the impossibility of man to stand before God, who judges the heart, in their own righteousness. The believer being the partaker of the divine nature, is righteous and loves his brother. Only the reception of eternal life, which is Christ Himself, can produce righteousness and love. "Whosoever has been begotten of God does not practice sin, because His seed abides in him and he cannot sin, because he has been begotten of God. In this are manifest the children of God and the children of the devil. Whoever does not practice righteousness is not of God, and he who does not love his brother" (1 John 3:9-11). The believer walking in the Spirit will in no way fulfill flesh's lust.

"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.

The sixth commandment: "Thou shalt not kill"

The Lord Jesus begins the first of the six examples with the words, "Ye have heard that it was said to the ancients" (A.V.-"them of old time"). The "ancients" here are not only the contemporaries of Moses, since the following text contains an addition to the original commandment. The audience of the Lord Jesus had heard two things: First, that the commandment, "Thou shalt not kill," was given by God, and second, what they knew had probably been added by the scribes since the Babylonian captivity, "and whosoever shall kill shall be in danger of the judgment." It would seem that "judgment" here means the judges and officers mentioned for example in Deuteronomy 16: 18 who were to be appointed in every town in Israel.