Genesis 4:18

Unto Enoch was born Irad. Of the following generations only names are mentioned. The names resemble those of some of Seth’s descendants, as for instance Irad and Jared, Mehujael and Mahalaleel, Methusael and Methuselah, Cain and Cainan, but the names of Enoch and Lamech occur in both families. Critical scholars have considered this as proof that the two genealogical tables are simply different forms of one original legend. However, similarity in names in no way implies identity of persons. For instance, the name Korah appears in the families of Levi (Ex. 6:24) and Esau (Gen. 36:5), and Enoch is the name not only of Cain’s son and one of Seth’s pious descendants but also of the eldest son of Reuben (ch. 46:9), and of a son of Midian (ch. 25:4). The character of Enoch the son of Cain is in such distinct contrast to that of Enoch in the line of Seth as to preclude identifying the two as one individual.

As to the other pairs of names, similarity is only superficial. The names in Hebrew, as in English, are not identical either in spelling or in meaning. For example, Irad has been translated as “townsman” or “ornament of a city,” Jared as “descent.” Mehujael may mean either “smitten of God” or “destroyed of God”; Mahalaleel, “praise of God.” Methusael has the meaning “man of God” or “man of prayer”; Methuselah, “man of growth.” The meaning of Lamech is not known.