Genesis 4:24
22 Now Zillah also gave birth to Tubal-Cain, who heated metal and shaped all kinds of tools made of bronze and iron. The sister of Tubal-Cain was Naamah. 23 Lamech said to his wives, “Adah and Zillah, listen to me! You wives of Lamech, hear my words! I have killed a man for wounding me, a young man for hurting me. 24 If Cain is to be avenged seven times as much, then Lamech seventy-seven times!” 25 And Adam was intimate with his wife again, and she gave birth to a son. She named him Seth, saying, “God has given me another child in place of Abel because Cain killed him.”
Matthew 18:21
20 For where two or three are assembled in my name, I am there among them.” 21 Then Peter came to him and said, “Lord, how many times must I forgive my brother who sins against me? As many as seven times?” 22 Jesus said to him, “Not seven times, I tell you, but seventy-seven times! 23 “For this reason, the kingdom of heaven is like a king who wanted to settle accounts with his slaves.
Notes and References
"... Jesus’ hyperbolic reply to Peter’s query requires additional comment. To Peter’s query whether to forgive a fellow disciple’s sins seven times is generous, Jesus offers a hyperbolic response, “I do not say up to seven times, but up to seventy-seven times.” Though Peter may seem magnanimous compared to a stingier standard of forgiveness the rabbis taught, his big-heartedness falls short of the lavishness Jesus requires. It is likely that Peter derives his number from Scripture’s frequent use of “seven times” for avenging evildoers, first with reference to the Lord’s protecting the life of Cain by threatening sevenfold avenging of anyone who would slay him (Genesis 4:15; Leviticus 26:21, 28; Deuteronomy 28:25; Psalm 79:12; Proverbs 6:31; compare Luke 17:4). If this is correct, then Jesus’ reply may allude to Genesis 4:24, to Lamech’s use of seventy-seven times. Lamech appeals to lex talionis to reason that if Cain, who murdered his brother out of malice, could be avenged sevenfold, then his own avengement ought to be seventy-sevenfold, an exaggerated number, because he killed in self-defense. Likewise, Jesus exaggerates Peter’s number, to emphasize that remission is boundless ..."
Caneday, Ardel B. Lavishly Forgive Sins in order to Be Forgiven: Jesus’ Parable of the Unmerciful Servant (pp. 17-32) The Evangelical Review of Theology and Politics, Vol. 5, 2017