I am quoting David Flusser’s book, Jewish Sources in Early Christianity (p.59). Though not an evangelical believer, Flusser writes:
“Since the age of the Hasmoneans, Jews had believed that the saints who died to sanctify the name of God atoned for the sins of Israel. The story of the mother and her seven sons in the Second Book of Maccabees acquires a greater significance in the Fourth Book of Maccabees, where their death is seen as an atoning sacrifice. In another Jewish source, Midrash Sifre, the idea is expressed that the killing of the Children of Israel by the Gentiles atones for the former’s sins.
“It is reasonable to assume that during the Roman period this idea was applied not only to Jesus, but also to all those who were executed by the authorities. Even Jews who did not accept Christianity evidently believed that Jesus, like the other martyrs of the Roman authorities, had atoned for the sins of Israel.”