The original-language words variously rendered “kill,” “murder,” and “slay” refer to the taking of a life, the context or other scriptures determining whether the deliberate and unauthorized or unlawful taking of another person’s life is involved. For example, in the command, “You must not murder” (Ex 20:13), the Hebrew word for “murder” (ra·tsachʹ) here clearly refers to deliberate and unlawful killing. But at Numbers 35:27 the same term denotes an act that an avenger of blood was authorized to carry out. Therefore, the command, “You must not murder,” has to be understood within the framework of the entire Mosaic Law, which authorized the taking of human life under certain circumstances, as in the execution of criminals.

Early History. Almost from the beginning of human history, murder has been known. Through his disobedience, the first man Adam passed sin and death to his offspring, thus, in effect, proving himself to be a murderer. (Ro 5:12; 6:23) It was the Devil who deliberately contributed to this development by inducing Adam’s wife Eve to sin, thus himself becoming a manslayer, a murderer, at the beginning of his course as a slanderer of God.​—Ge 3:13; Joh 8:44.

Less than 130 years afterward, the first violent murder, a fratricide, occurred. Cain, Adam’s firstborn son, motivated by envious hatred, murdered his righteous brother Abel. (Ge 4:1-8, 25; 5:3) For this act Cain was cursed in banishment to become a wanderer and a fugitive in the earth. (Ge 4:11, 12) Not until after the Flood of Noah’s day did God authorize humans to administer capital punishment for murder.​—Ge 9:6.

Under the Law. Centuries later the Mosaic Law was given to the Israelites, and it included extensive legislation regarding the taking of human life. It differentiated between deliberate and accidental slaying. Factors considered as weighing against a person claiming to be an accidental manslayer were: If he (1) had been a former hater of the slain person (De 19:11, 12; compare Jos 20:5), (2) had lain in wait for the victim (Nu 35:20, 21), or (3) had used an object or implement capable of inflicting a mortal wound (Nu 35:16-18). Even slaves, if killed while being beaten by their masters, were to be avenged. (Ex 21:20) Whereas the death penalty was prescribed for deliberate murderers and a ransom was ruled out in their case, unintentional manslayers could preserve their lives by availing themselves of the safety accorded them in the cities of refuge.​—Ex 21:12, 13; Nu 35:30, 31; Jos 20:2, 3; see CITIES OF REFUGE.

Certain deliberate acts that indirectly caused or could have resulted in the death of another person were considered tantamount to deliberate murder. For example, the owner of a goring bull who disregarded previous warnings to keep the animal under guard could be put to death if his bull killed someone. In some cases, however, a ransom could be accepted in place of the life of the owner. Undoubtedly the judges would take circumstances into consideration in such a case. (Ex 21:29, 30) Also, an individual scheming to have another person killed by presenting false testimony was himself to be put to death.​—De 19:18-21.

The Law permitted self-defense but restricted an individual’s right to fight for his property. Bloodguilt came upon a person who, though catching a thief in the act of breaking into his home, killed the lawbreaker in the daytime. This was evidently because thievery did not carry the death penalty, and the thief could be identified and brought to justice. At night, however, it would be difficult to see what one was doing and to ascertain the intentions of an intruder. Therefore, the person killing an intruder in the dark was considered guiltless.​—Ex 22:2, 3.

In the first century C.E. those seeking to kill Jesus were identified as ‘children of the Devil,’ the first manslayer. (Joh 8:44) The scribes and Pharisees decorated the tombs of righteous ones, claiming that they would not have been sharers in putting the prophets to death. Yet they manifested the same murderous spirit toward the Son of God.​—Mt 23:29-32; compare Mt 21:33-45; 22:2-7; Ac 3:14, 15; 7:51, 52.

Hatred Equated With Murder. Murders issue forth from the heart of an individual. (Mt 15:19; Mr 7:21; compare Ro 1:28-32.) Therefore, anyone hating his brother would be a manslayer, a murderer. (1Jo 3:15) Christ Jesus also associated  murder with wrong attitudes such as an individual’s continuing wrathful with his brother, speaking abusively to him, or wrongly judging and condemning him as a “despicable fool.” (Mt 5:21, 22) Such hatred may lead to actual murder. It appears that the words of James (5:6), “You have condemned, you have murdered the righteous one,” may be understood in this light. Wicked rich persons who showed hatred for genuine disciples of God’s Son and took oppressive action against them did in some instances actually murder these Christians. As treatment accorded to his brothers is considered by Christ Jesus to be meted out to him, these persons had also figuratively murdered him, and James evidently had that in mind.​—Compare Jas 2:1-11; Mt 25:40, 45; Ac 3:14, 15.

Although followers of Christ might be persecuted and even murdered for righteousness’ sake, they were not to be found suffering for having committed murder or other crimes.​—Mt 10:16, 17, 28; 1Pe 4:12-16; Re 21:8; 22:15.