Is it OK to add to the law of Moses?
Deuteronomy prohibits altering the commandments, while later teachings explicitly extend or replace earlier formulations of permitted conduct.
- Textual conflict
- Interpretive tension
- The passages pull in different directions, but the conflict depends on how their wording, scope, or narrative context is read.
- Importance
- Major
- A major event or claim with wider implications.
A prohibition on altering Mosaic commands conflicts with later authoritative expansions and reversals, particularly the replacement of regulated oaths with no oaths.
An editorial assessment of the quoted passages. Importance describes the stakes; it does not increase certainty. Reading order weighs both.
Moses forbids adding to or removing from the commandments
Ye shall not add unto the word which I command you, neither shall ye diminish ought from it, that ye may keep the commandments of the Lord your God which I command you.
Jesus and Paul impose further rules on conduct
Ye have heard that it was said by them of old time, Thou shalt not kill; and whosoever shall kill shall be in danger of the judgment: But I say unto you, That whosoever is angry with his brother without a cause shall be in danger of the judgment: and whosoever shall say to his brother, Raca, shall be in danger of the council: but whosoever shall say, Thou fool, shall be in danger of hell fire.
Ye have heard that it was said by them of old time, Thou shalt not commit adultery: But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart.
It hath been said, Whosoever shall put away his wife, let him give her a writing of divorcement: But I say unto you, That whosoever shall put away his wife, saving for the cause of fornication, causeth her to commit adultery: and whosoever shall marry her that is divorced committeth adultery.
Whosoever putteth away his wife, and marrieth another, committeth adultery: and whosoever marrieth her that is put away from her husband committeth adultery.
And unto the married I command, yet not I, but the Lord, Let not the wife depart from her husband: But and if she depart, let her remain unmarried, or be reconciled to her husband: and let not the husband put away his wife.
Again, ye have heard that it hath been said by them of old time, Thou shalt not forswear thyself, but shalt perform unto the Lord thine oaths: But I say unto you, Swear not at all; neither by heaven; for it is God’s throne: Nor by the earth; for it is his footstool: neither by Jerusalem; for it is the city of the great King. Neither shalt thou swear by thy head, because thou canst not make one hair white or black.
Ye have heard that it hath been said, An eye for an eye, and a tooth for a tooth: But I say unto you, That ye resist not evil: but whosoever shall smite thee on thy right cheek, turn to him the other also.
Ye have heard that it hath been said, Thou shalt love thy neighbour, and hate thine enemy. But I say unto you, Love your enemies, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you, and persecute you;
Understanding the contradiction
Deuteronomy 4:2 forbids adding to the commanded word or diminishing it. The purpose is faithful observance of the commandments as given. Matthew 5:21-22 then contrasts an earlier prohibition of killing with Jesus' judgment on causeless anger and insulting speech. Matthew 5:27-28 similarly extends adultery into lustful looking. These rules reach conduct beyond the acts named in the earlier formulations quoted by Jesus.
Other examples change the practical direction more sharply. Matthew 5:33-36 moves from honoring oaths to not swearing them. Matthew 5:38-39 sets nonresistance beside retaliation, while Matthew 5:31-32 and Luke 16:18 restrict divorce and remarriage. 1 Corinthians 7:10-11 presents further marital instructions as the Lord's command. The repeated 'But I say' explicitly distinguishes the later instruction from what listeners have heard. The tension is therefore between preserving a received command without addition and accepting new authoritative requirements. The excerpts do not themselves establish that every earlier saying Jesus cites is a verbatim Mosaic law, but several plainly increase or alter the obligations being described.