1. The commandment prohibiting murder is explicitly stated to Noah by God: "Whoever sheds the blood of man, by man shall his blood be shed, for He made man in the image of God" (Gen. 9:6).
2. A Noahide who kills a human being, even a baby in the womb of its mother, receives the death penalty. This means that one who strikes a pregnant woman, thereby killing the fetus, incurs the death penalty. (The act must have been done at least forty days after conception. Before forty days, the act is in the category of destruction of man's seed, and the transgressor is liable for punishment from heaven, not by a court on earth.)
3. Men and women have an equal responsibility to observe the prohibition against murder, and any act for which a man is held liable, a woman is equally held liable.
4. If a person kills one who is terminally ill or is falling from the top of a cliff or is certain to die momentarily for any other reason, he transgresses the prohibition against murder and is liable for punishment by the courts. This judgment places the idea of mercy killing or euthanasia squarely in the category of murder.
5. If one pushes a person onto railway tracks and a train subsequently comes and kills him, or if one leaves a person in a situation where he will surely starve to death, although the action only indirectly causes the person's death, it is murder and the act is punishable by the courts.
6. If a person sees someone pursuing another for the obvious or suspected intent of committing murder or with the intent of causing the pursued to commit a sin, and the observer is able to stop the pursuer by wounding him, but kills him instead, he transgresses this commandment and receives the death penalty. If, however, the person himself is being pursued, he is free to take any action necessary to save his own life.
7. Authorities disagree as to whether it is permissible for a Noahide to kill a fetus in order to save the life of the mother. But all agree that taking the mother's life to save the fetus is murder and punishable by the courts.
8. If a Noahide kills someone through a messenger, both the messenger and the one who sent him are liable for punishment as murderers.
9. A person is commanded to allow himself to be killed rather than kill. This means that if people try to compel a person on pain of death to kill someone, he must not commit murder regardless of the consequences.
10. Suicide is forbidden under the Seven Universal Laws.
11. There is no place of legal refuge for a murderer. Any relative (on the father's side) of a murder victim who can legally inherit property of the deceased may designate himself a "blood avenger." If the murder was committed intentionally with malice aforethought, it is the blood avenger's obligation to see that the murderer is brought to trial.
12. If the killing was manslaughter ‑ that is, if the killer acted unintentionally but negligently, and it is a matter of a ger toshav (proselyte at the gate, a Noahide who lives according to the Seven Universal Commandments) killing another ger toshav, the killer flees to a designated city of refuge until his trial comes up. If the courts rule that he did kill but unintentionally, he must return to the city of refuge and reside there until the High Priest of the Jews dies (the death of the righteous is an atonement for the generation), then he is free to return to his home. If he leaves the city of refuge prior to the death of the High Priest, the blood avenger may find him and kill him. The blood avenger is held harmless for killing the manslaughterer.
If a ger toshav kills an Israelite unintentionally but negligently, or if he kills another ger toshav because he thought that it was permissible (this is considered tantamount to killing intentionally), he is liable for the death penalty.
If a Noahide who does not live according to the Seven Universal Commandments kills another Noahide in a circumstance of manslaughter, he is subject to the death penalty and the city of refuge affords him no protection.
In any case where a blood avenger kills the manslaughterer, if a relative of the slain manslaughterer seeks revenge against the blood avenger and kills him, that relative is deemed a murderer and is prosecuted as such.
13. There is a difference of opinion as to whether the Seven Universal Commandments include the commandment forbidding the willful destruction of a man's seed through masturbation or any other act of wasting semen. All agree, however, that sexual relations with a woman who is incapable of bearing children is not considered wasting semen. One opinion is that the commandment to be fruitful and multiply, having been given to Noah, but not repeated to Moses, was in force only during those generations before the historical event of Mount Sinai. In those early times, wasting semen was considered among the most heinous of sins and a chief reason that God brought the Flood to destroy the world. Moreover, the Torah clearly teaches that Judah's two sons, Er and Onan, were killed by God, for "the thing which he (Onan) did was evil in the eyes of the Lord" (Gen. 38:10). But this event also occurred before the giving of the Torah on Mount Sinai. This opinion concludes that since the commandment against wasting seed was not repeated at Mount Sinai, it is no longer in effect as part of the Seven Universal Commandments.
The other opinion states that despite its not being repeated at Mount Sinai,
since it was originally part of the Seven Universal Commandments, a man must not willfully destroy his seed, though the act is not punishable by the courts. After a man has fulfilled his minimal obligation of bringing a son and a daughter into the world, if he wishes then to use contraceptive devices, he should use those types that do not act directly on the semen. Also, according to this viewpoint, masturbation would be strictly forbidden.
In spiritual terms, the reason for the great concern and strictness concerning the wasting of a man's seed is that it is considered the willful destruction of his life‑giving force and equated with life itself. Therefore, the destruction of a man's seed is related closely to murder, and more, to the murder of his own children.
 Mishneh Torah, Laws of Kings, chapter 9, law 4
 Shulchan Arukh, Yoreh Deah, chapter 305, law 23
 Babylonian Talmud, Sanhedrin 57b
 Mishneh Torah, Laws of Kings, chapter 9, law 4
 Ibid., Laws of Wounds and Damages, chapter 8, law 10, see commentary of Mishneh l'Melech
 Babylonian Talmud, Sanhedrin 59a, Tosefos, "There is nothing known..."
 Bereshit Rabba, chapter 34; Mishneh Torah, Laws of Murder and Guarding the Soul, chapter 2, law 2
 Ibid., Laws of Kings, chapter 10, law 2
 Gen. 9:5, commentary of Rashi
 Mishneh Torah, Laws of Kings, chapter 10, law 1; Laws of Murder and Guarding the Soul, chapter 5, laws 3 and 4
 Shulchan Arukh, Even HaEzer, chapter 23, law 5, the RaMoh (Rabbi Moses Isserles)
 Babylonian Talmud, Sanhedrin 59b, Tosefos, "Behold, be fruitful and multiply." .
 Mishneh Torah, Laws of Kings, chapter 10, law 7, Mishneh l'Melech. "We return to the words of the Rashbah..."