One of the popular myths about Judaism is that there is no place in Jewish thought for the idea that someone can die for the sins of another person
Yet both the Bible and Jewish tradition have much to say about dying so that another might have forgiveness.
In the Hebrew Bible, normally the death of an animal substituted for the death of a person who had sinned. In that way the death penalty for the Israelite was averted as the animal went to its fate instead.
But at times the death of another human being atoned for the sins of the people. Three such biblical passages are Numbers 25:1-8; Exodus 32; and Second Samuel 21:1-14. In the first, the death of two people by the hand in Phinehas stops a plague against the people; in the second, the death of a large number of Israelites does the same thing; in the third, the impaling of the sons of King Saul again atones for the sins of the people. Make no mistake: it is the death of people that stops the plague or averts God's wrath. Rabbi Jacob Milgrom comments:
Phinehas's deed in slaying one Israelite leader suffices to ransom (kipper) Israel; God requires no additional victims. Kipper functions to avert the retribution, to nip it in the bud, to terminate it before it is fully exhausted.
Jacob Milgrom, The JPS Torah Commentary: Numbers (Philadelphia; New York: The Jewish Publication Society, 1990), p. 477.
Milgrom mentions two other texts where the death of human beings functions to secure atonement:
The first, Exodus 32:26-29, deals with the apostasy of the golden calf where the Levites are called upon to slay the people, even their close relatives, indiscriminately -- to assuage the wrath of God. The second text, 2 Samuel 21:1-14. . .[shows that] the impalement of Saul's sons provided the needed ransom-expiation for ending the drought.
Ibid., p. 478
Likewise, in cases of accidental manslaughter, the killer would flee to a "city of refuge," but could not leave until the death of the high priest (Numbers 35:25-32). The high priest's death atoned for the manslaughterer's sin so that he himself could go free. This interpretation is held not only by Christians but is also found in the Talmud (Makkoth 11b):
If after the slayer has been sentenced as an accidental homicide the high priest dies, he need not go into exile. But is it not the exile that expiates? It is not exile that expiates, but the death of the high priest.
Translation as given in Jacob Milgrom, Numbers (Philadelphia: Jewish Publication Society, 1990), p. 294. See likewise in Gordon J. Wenham, Numbers: An Introduction and Commentary (Downers Grove: InterVarsity Press, 1981), p. 238 n. 2
Milgrom comments: "As the High Priest atones for Israel's sins through his cultic service in his lifetime...,so he atones for homicide through his death."
Perhaps the most controversial passage that refers to atonement not just by the death of any human being, but through the sufferings and death of the Messiah, in Isaiah 52:13-53:12. In Talmudic times, this passage was understood to refer to the coming Messiah. In medieval times, especially under the influence of Rashi, the prevailing interpretation applied the passage to the people of Israel, though the messianic interpretation was still held by various sages. The relevant point here is that no one can object that the Isaiah passage is non-Messianic because God forbids human sacrifice. Though He surely forbids pagan sacrifice of human beings, there are examples where only the death of a guilty human being or the death of the priest can effect full atonement. Furthermore, the "servant" of Isaiah 53 voluntarily gives us his life; his death is not forced on him. In a later time, Jesus affirmed that his impending death was voluntary. Even though he seemed to go to death by the force of circumstance, he voluntarily placed himself in those circumstances, so that he could say: " lay down my life --only to take it up again. No one takes it from me, but I lay it down of my own accord" (John 10:17-18). And, "My command is this: Love each other as I have loved you. Greater love has no one than this, that he lay down his life for his friends" (John 15:12-13).
In Jewish thought, the death of a martyr can be redemptive and atoning.
That martyrdom somehow counteracts the menace of sin and, therefore, has a redemptive quality is decidedly an early rabbinic theme, though not necessarily a central one...."Expiation for the coming world" underlines the significance of the notion for the martyrs themselves. But, the rabbinic conception is not limited to penance for sin...
Aharon Agus, The Binding of Isaac and Messiah: Law, Martyrdom and Deliverance in Early Rabbinic Religiosity (Albany: State University of New York Press, 1988), pp. 40-41.
Though it includes that conception. When we speak of martyrs, we are speaking of human beings whose death has atoning value.