The following is from my book on MDR.
1. We must understand that, in the Sermon on the Mount, when Jesus said things like, “you have heard that it was said” (Matt. 5:21, 27, 31, etc.), He was not talking about what “Moses” said and taught, but what the “Scribes and Pharisees” were saying and teaching. As the religious teachers of the day, they had misunderstood, misapplied, and misused most of the things that God had intended in the moral requirements of the Law of Moses. They had either changed God’s commands altogether or misapplied what God had said in the commands. This is what Jesus was correcting in His teaching. The Law of Moses was “holy and just and good” in its moral precepts and commandments (Rom. 7:12). God did not “create” sin by giving the “law” through Moses. Sin already existed long before the Law of Moses was given.
2. We must keep in mind throughout the sermon that Jesus is both explaining and exposing. He is explaining what God actually meant in giving the moral requirements in the Law of Moses. And He was exposing what the Scribes and Pharisees were teaching about the Law. They had “made the commandment of God of no effect by their tradition” (Mt. 15:6). Jesus specifically told His disciples to “beware” of the teaching of the Pharisees (Mt. 16:12). They “justified themselves” (Lk. 16:15) and appeared righteous “outwardly,” but inwardly were full of hypocrisy and deceit. (Matt. 23:28).
3. In the Sermon on the Mount, Jesus taught them what the Law of Moses actually meant and, at the same time, exposed the Scribes and Pharisees for changing, corrupting, and making void God’s commandments by their false teaching. They were false teachers whom Jesus described as “wolves” in sheep’s clothing (Mt. 7:15).
4. In the sermon, notice how Jesus taught the same thing that Moses did. Jesus explained that when God said not to “murder,” He was not just talking about the “act” itself. He was also condemning the attitude of heart that leads to murder. He explained that the attitude that leads one to want to murder is the real problem and that we should seek to settle differences in the quickest and easiest way possible before it leads to all kind of problems—including wanting to murder someone else—and we bring judgment on ourselves. This same truth was taught in the overall teaching of the Old Testament. Jesus was not changing God’s moral law on this subject.
5. The Law of Moses taught the same thing about anger that Jesus did, because it taught men to “do unto others as you would have them do to you” (Mt. 7:12). The Law taught men to “Love your neighbor as yourself” (Lev. 19:18; Mt. 22:39-40). The Old Testament warns against “anger” and taught men to be careful what they say and do when they are angry just as Jesus did here.
Cease from anger, and forsake wrath; do not fret—it only causes harm. (Ps. 37:8).
A wrathful man stirs up strife, but he who is slow to anger allays contention. (Prov. 15:18).
The discretion of a man makes him slow to anger, and his glory is to overlook a transgression. (Prov. 19:11).
Do not hasten in your spirit to be angry, for anger rests in the bosom of fools. (Ecc. 7:9).
6. Obviously the Jewish leaders did not teach this and they certainly did not practice it. They only thought or taught that it is wrong to commit the “act” of murder but did not teach people what the Old Testament taught about the attitude that leads to murder. In doing so, they could justify themselves (Lk. 16:15) because they were angry with Jesus and others for no reason.
7. Consider also what Jesus taught about sexual sin.
You have heard that it was said to those of old, ‘You shall not commit adultery.’ But I say to you that whoever looks at a woman to lust for her has already committed adultery with her in his heart. (Matt. 5:27-28).
8. Jesus explained that when Moses gave this law, he was not just talking about the “act” itself, but also the lust in the heart that leads to committing the act. Moses himself taught that one should not “covet (desire/lust after) your neighbor’s wife” (Ex. 20:17). Moses and others in the Old Testament clearly taught that it is wrong for a man to lust after a woman in his heart.
And you shall have the tassel, that you may look upon it and remember all the commandments of the LORD and do them, and that you may not follow the harlotry to which your own heart and your own eyes are inclined, (Num. 15:39).
Do not lust after her beauty in your heart, nor let her allure you with her eyelids. (Prov. 6:25).
And there a woman met him, with the attire of a harlot, and a crafty heart…With her enticing speech she caused him to yield…Now therefore, listen to me, my children; Pay attention to the words of my mouth…Do not let your heart turn aside to her ways…(Prov. 7:6-27).
Who may ascend into the hill of the LORD? Or who may stand in His holy place? He who has clean hands and a pure heart… (Ps. 24:3-4).
9. The Pharisees were an “adulterous” generation (Mt. 16:4). They were full of “uncleanness” (Mt. 23:27). According to Strong’s Concordance, the word “uncleanness” means: “in a moral sense: the impurity of lustful, luxurious, profligate living.” When we look at the other ten times this word is used in the New Testament, it is obvious that it refers primarily to “sexual uncleanness.” (See Rom. 1:24; 6:19; 2 Cor. 12:21; Eph. 4:19; 5:3, 5; Col. 3:5; 1 Thess. 2:3; 4:7; 2 Pet. 2:10). Therefore, the Scribes and Pharisees were obviously lusting after women and sometimes putting their faithful wives away in order to marry them. In other cases, they were breaking up marriages in order to get the women they wanted. This is, no doubt, one of the reasons Jesus brought the subject up about committing adultery in the heart. He was not only teaching that it is sin, but also condemning the Jewish leaders and others who were full of sexual uncleanness (Mt. 23:27).
“Furthermore it has been said, ‘Whoever divorces his wife, let him give her a certificate of divorce.’ But I say to you that whoever divorces his wife for any reason except sexual immorality causes her to commit adultery; and whoever marries a woman who is divorced commits adultery. (Matt. 5:31).
10. This was a part of what Moses taught, but not in the sense that the Pharisees had interpreted it. They had conveniently left part of what Moses said completely out. Moses did not just say that a man could divorce his wife by simply giving her a “certificate of divorce” and sending her away. Moses said if he found some “uncleanness” in her, he could put her away. Jesus explained that the husband who put her away must do so because he has found some “sexual immorality” in her, which is exactly what Moses had taught. Otherwise, he causes it to appear that she has committed “uncleanness” or “sexual immorality.” By putting her away he causes it to appear that she has “broken the marriage covenant” and is guilty of “uncleanness” (or marital adultery). See Deuteronomy 24:1-4.
11. As with the other subjects, the Pharisees were teaching that a man could put away his faithful wife for “any cause” as long as he gave her the “bill of divorcement.” She did not have to be guilty of “uncleanness” like Moses actually said. They obviously taught that one does not sin by putting away his faithful wife in order to marry someone else, but Jesus said doing so “causes her” to “commit adultery,” even if she is not guilty of doing anything wrong.
12. And whoever marries one who is “put away” because of “uncleanness” or “sexual immorality” is committing adultery because he is also responsible for breaking up the marriage covenant between a husband and wife. I believe that the reason Jesus said this is because the Pharisees, who were “adulterous” (Mt. 16:4) and full of (sexual) “uncleanness” (Mt. 23:27), were committing fornication with other men’s wives and causing them to be put away, thus destroying the marriage covenant between that couple. And, of course, the same thing happens today. Anyone who causes the break up of a marriage is “committing adultery” against the innocent marriage partner in that marriage that he helps breaks up.
13. “Again you have heard that it was said to those of old, ‘You shall not swear falsely, but shall perform your oaths to the Lord’ (Matt. 5:33). This is what Moses taught, but the Pharisees had corrupted what Moses taught to such an extent that they taught that it was right to lie and not even tell the truth at all. The Pharisees obviously taught that the only oaths that one had to perform were those made “to the Lord” and they were the ones who decided which oaths were made to the Lord and which were not. In other words, they decided which oaths were binding and which oaths were not. Jesus made this clear when He was condemning their hypocrisy in Matthew 23. Observe the reading:
“Woe to you, blind guides, who say, ‘Whoever swears by the temple, it is nothing; but whoever swears by the gold of the temple, he is obliged to perform it. Fools and blind! For which is greater, the gold or the temple that sanctifies the gold? And, ‘Whoever swears by the altar, it is nothing; but whoever swears by the gift that is on it, he is obliged to perform it.’ Fools and blind! For which is greater, the gift or the altar that sanctifies the gift? Therefore he, who swears by the altar, swears by it and by all things on it. He, who swears by the temple, swears by it and by Him who dwells in it. And he, who swears by heaven, swears by the throne of God and by Him who sits on it. (Mt. 22:16-22).
14. Observe that the Scribes and Pharisees taught that it was not a binding oath if one swears a certain way. In other words, one could swear by the temple that he was telling the truth and yet be lying and it would not be wrong to lie as long as he did not swear by the gold of the temple. This is the kind of ungodly teaching that Jesus was correcting in the Sermon on the Mount.
15. “You have heard that it was said, ‘An eye for an eye and a tooth for a tooth.’ But I tell you not to resist an evil person. But whoever slaps you on your right cheek, turn the other to him also” (Matt. 5:38-39). The Pharisees were obviously teaching that this command applies to personal vengeance. In other words, whatever someone does to hurt you, you can do the same to them. Jesus explained that Moses was not referring to personal vengeance when he wrote this command. God never taught personal vengeance against others.
16. When Moses said “eye for eye” he was referring to the right of the government to exercise vengeance on evildoers. It was and is God’s way of executing wrath on murderers and the like. Observe what Moses actually said:
“One witness shall not rise against a man concerning any iniquity or any sin that he commits; by the mouth of two or three witnesses the matter shall be established. If a false witness rises against any man to testify against him of wrongdoing, then both men in the controversy shall stand before the LORD, before the priests and the judges who serve in those days. And the judges shall make careful inquiry, and indeed, if the witness is a false witness, who has testified falsely against his brother, then you shall do to him as he thought to have done to his brother; so you shall put away the evil from among you. And those who remain shall hear and fear, and hereafter they shall not again commit such evil among you. Your eye shall not pity: life shall be for life, eye for eye, tooth for tooth, hand for hand, foot for foot” (Deuteronomy 19:15-21).
17. Observe that it was the judges who were to render the verdict for punishment for sins and this only after “careful inquiry” and on the testimony of “witnesses.” This has nothing to do with God authorizing personal vengeance against another person.
18. The Law of Moses taught that if someone was breaking into a person’s house, that person could kill him as a matter of personal protection. But one was not allowed to go out later and hunt him down and kill him as a matter of personal vengeance. Notice what Moses said:
If the thief is found breaking in, and he is struck so that he dies, there shall be no guilt for his bloodshed. If the sun has risen on him, there shall be guilt for his bloodshed. (Exodus 22:2-3).
19. Observe that personal protection is allowed, while personal vengeance is denied. Jesus explained that God taught us to do good to others and not retaliate. As a matter of fact, Jesus Himself said that a man would not allow his house to be broken into (Matt. 24:43), but He, like Moses, also forbids taking personal vengeance (Matt. 5:39-42).
20. The Law and the prophets taught, “do unto others as you would they do to you” (Matt. 7:12) and to love your neighbor as “yourself’ (Matt. 22:39-40). This is exactly what Jesus is explaining in the Sermon on the Mount. Jesus is emphasizing that God has always wanted us to “overcome evil with good.”
21. The Old Testament taught the exact same thing as Jesus did in this sermon. God said, through Moses, “Vengeance is mine and recompense” (Deut. 32:35). Paul’s application of this statement is in the New Testament in Romans 12:19-21 which reads as follows:
Beloved, do not avenge yourselves, but rather give place to wrath; for it is written it is written “Vengeance is Mine, I will repay,” says the Lord. Therefore “If your enemy is hungry, feed him; if he is thirsty, give him a drink; for in so doing you will heap coals of fire on his head.” Do not be overcome by evil, but overcome evil with good.
22. Observe that Paul told the saints in Rome not to “avenge yourselves.” Why? Because of what God had “written” in the Old Testament in Deuteronomy 32:5 and reaffirmed by both Jesus in the Sermon on the Mount and Paul in Romans.
23. Consider also that Jesus said:
“You have heard that it was said, ‘You shall love your neighbor and hate your enemy.’ But I say to you, love your enemies, bless those who curse you, do good to those who hate you, and pray for those who spitefully use you and persecute you, (Matt. 5:43-44).
24. Moses did teach that we should love our neighbors, which the Pharisees were right about. But he did not teach that we are to “hate” our enemies. In fact, Moses taught what Jesus did. Like Jesus, He taught that men were to “do good to enemies.” Observe what Moses wrote:
If you meet your enemies’ ox or his donkey going astray, you shall surely bring it back to him again. If you see the donkey of one who hates you lying under its burden, and you would refrain from helping it, you shall surely help him with it. (Ex. 23:4-5).
25. The Old Testament taught almost word for word what the New Testament does about enemies. Read it for yourself for Proverbs 25:21-22: “If your enemy is hungry, give him bread to eat; and if he is thirsty, give him water to drink; for so you will heap coals of fire on his head, and the LORD will reward you.”
26. We must keep in mind throughout the sermon that Jesus is not contrasting what He said with what God said through Moses, but rather what “has been said” by the Jewish false teachers for years.