23 Lamech said to his wives: “Adah and Zillah, hear my voice; you wives of Lamech, listen to what I say: I have killed a man for wounding me, a young man for striking me. 24 If Cain’s revenge is sevenfold, then Lamech’s is seventy-sevenfold.”
Lamech is fifth in the line of lineal descent from Cain. His name means “powerful.”
23. a man for wounding me] Lamech boasts that he has slain a man who had wounded him and a young man who had bruised him. Whether “a man” and “a young man” are the same person, or whether they mean a man and his son, cannot be decided. Lamech has exacted the vengeance of death for the insult of a blow2.
 See for an explanation by Jewish tradition Appendix B.
It is, however, possible that the poem only describes an imaginary instance in which Lamech had retaliated in self-defence, and boasts that with the assistance of metal weapons Lamech’s capacity for revenge is increased elevenfold.
23, 24. The Song of the Sword. These verses are written in a poetical style, with the parallelism of clauses characteristic of Hebrew poetry. It is the first instance of Hebrew poetical composition in the Bible1. It contains (1) the address of Lamech to his wives; (2) the announcement of a recent exploit; (3) the boast of confidence and security against injury or insult. It is generally supposed that Lamech’s Song is intended to represent his exultation after the invention of metal weapons by his son Tubal-Cain. The new possession inspired primitive man with confidence and eagerness for savage retaliation.
 See G. Adam Smith’s Early Poetry of Israel, p. 21 (Schweich Lectures, 1910).
The substance of line (or stichos) 1 is repeated in line (or stichos) 2: “Adah and Zillah” correspond to “Ye wives of Lamech,” and “Hear my voice” to “Hearken unto my speech.”
In line (or stichos) 3, the word “I have slain” gives the note to the whole distich; but “a man for wounding me” is repeated in greater detail in line (or stichos) 4, “a young man for bruising me.” Line (or stichos) 5 mentions the traditional vengeance prom
As you might note from the comment above, verses 23 and 24 are the first instance of Hebrew poetry in the Bible.
These verses, and those that preceded them, are intended condemnation of the sinful direction of the line of Cain.
(23, 24) Lamech said . . . —Following quickly upon music, we have poetry, but it is in praise of ferocity, and gives utterance to the pride of one who, by means of the weapons forged by his son, had taken violent revenge for an attack made upon him. Many commentators, however, regard the poem as hypothetical. “Were any one to wound me, I would with these weapons slay him.” It would thus be a song of exultation over the armour which Tubal-cain had invented. It more probably records a fact, and is intended to show that, side by side with progress in the material arts, moral degradation was going on. Cain’s own act is spoken of, not as a sin to be ashamed of, but as a deed of ancient heroism: not comparable, however, with the glory of Lamech, whose wrath shall be ten-fold. The poetry is vigorous, and marked by that parallelism which subsequently became the distinguishing quality of Hebrew verse. It should be translated:—
“Adah and Zillah, hear my voice,
Ye wives of Lemech. give ear unto my rede.
For I have slain a man for wounding me:
Even a young man for bruising me.
Truly Cain shall be avenged sevenfold,
And Lemech seventy and sevenfold.”
It is remarkable that both of the words used for the attack upon Lamech refer to such wounds as might be given by a blow with the fist, while his word means to pierce, or run through with a sharp weapon. “Young man” is literally child, but see on Genesis 21:14.
With this boastful poem in praise of armed violence and bloodshed, joined with indications of luxury and a life of pleasure, the narrator closes the history of the race of Cain.
Keeping in mind the names we have seen here and in the previous verses, in the line of Cain’s descendants, we will revisit the line of Adam again in our next set of verses.