The focus of the story is on three children of Lamech, the first of which is Iabal. Even if it is a proper name, it is interesting to observe its derivation, even if not emphasized in dictionaries. The proper name Iabal is exactly the same as Iabal (same consonants and same vowels) which means watercourse (see Is 30:25). Also the name of the brother Iubal is linked with the Hebrew name which means river and also the third, although in a more indirect way (Tubal qayin – Cf. Gen 4:21-22).
As stated in the last article, in these chapters (Genesis 3-6), the author emphasizes how humanity – because of its actions – runs towards the flood, that is towards total destruction. The destructive aquatic element, it seems here to emerge through the names of the three sons of the violent Lamech. It is a river that will swell more and more its waters, up to overwhelm everything, just like violence and corruption that tears the heart of man (Cf. Genesis 6).