Genesis 4:24

24 Because vengeance has been exacted seven times on Cain's behalf, on Lamech's seventy times seven.

Genesis 4:24 Meaning and Commentary

Genesis 4:24

If Cain shall be avenged sevenfold, truly Lamech seventy
and sevenfold.
] Which if understood of him as confessing and lamenting his sin of murder, the sense is, if Cain was so severely punished for killing one man, of how much sorer punishment am I deserving, and shall have, who have killed two persons, and that after I had seen the punishment of Cain, and yet took no warning by it? or if he that killed Cain, who slew his brother, was to be avenged sevenfold, or to seven generations, then how much more, or longer, shall he be avenged, that shall slay me, who have slain none, or however not designedly; and therefore you may be easy and quiet, your fears, either from God or man, are groundless.

Genesis 4:24 In-Context

22 And Sella also bore Thobel; he was a smith, a manufacturer both of brass and iron; and the sister of Thobel was Noema.
23 And Lamech said to his wives, Ada and Sella, Hear my voice, ye wives of Lamech, consider my words, because I have slain a man to my sorrow and a youth to my grief.
24 Because vengeance has been exacted seven times on Cain's behalf, on Lamech's seventy times seven.
25 And Adam knew Eve his wife, and she conceived and bore a son, and called his name Seth, saying, For God has raised up to me another seed instead of Abel, whom Cain slew.
26 And Seth had a son, and he called his name Enos: he hoped to call on the name of the Lord God.

The Brenton translation of the Septuagint is in the public domain.