Genesis 4:18

The line of Cain is then outlined. In accordance with ancient genealogies only important descendants would be listed and the length of time to Lamech may have been considerable. The similarity to names in the line of Seth need not surprise us. They came of the same family roots and similarity of names is to be expected over time. The only name which is the same in both cases is Lamech, and the Lamechs are clearly distinguished. Besides we have here only the Hebrew forms of the names. Originally they would have been in some primitive language. Thus the similarity may be due to the translator's licence in order to suggest kinship.

The list is deliberately made up of seven names in order to show completeness and acceptability to God, for seven indicates divine completeness. It is noteworthy that whatever Cain's past there appears to be a determination to establish his family's continual trust in God - Enoch is ‘dedicated'; some of the line include El in their names (in a name El can be short for God); seven, the divine number, are listed in descent, and Lamech appeals to Yahweh's covenant with Cain. Furthermore Mehujahel means ‘God blots out' while Methushael means ‘man of God' (Akkadian ‘mutu-sa-ili') suggesting a moving back to a conscious hope of acceptability before God. The fact that these covenants are incorporated into Genesis 1-11 show that some connection between the descendants of Cain and the descendants of Seth was established so that they were considered part of the family history. The former covenant would certainly have to be communicated in order to be effective.