Genesis 4:24

Seventy times. A similar expression occurs, Matthew xviii. 22, to denote a great but indefinite number. God had promised to revenge the murder of Cain seven fold, though he had sinned voluntarily; so Lamech hopes that, as he had acted by mistake, and blinded by passion, in striking the stripling, the son of Tubalcain, he would deserve to be protected still more from falling a prey to the fury of any other. But many reject this tradition as fabulous, unknown to Philo, Josephus, &c. Moses no where mentions the death of Cain. Some, therefore, understand this passage with an interrogation; as if, to convince his wives that his sin was not so enormous as was supposed, he should say, Do not think of leaving me. What! have I killed a young man, as Cain did Abel, and still he is suffered to live unmolested; or have I beaten any one so that I should be punished? Onkelos, in effect, puts a negation to the same purport, "I have not killed, &c.:" (Calmet) others understand this passage, as if Lamech considered his crimes as much more grievous than even those of Cain. (Tirinus)