And Methuselah lived after he begat Lamech seven hundred eighty and two years, and begat sons and daughters:

King James Translators' Notes

Lamech: Heb. Lemech

Jamieson-Fausset-Brown Bible Commentary

26. Lamech-a different person from the one mentioned in the preceding chapter [Ge 4:18]. Like his namesake, however, he also spoke in numbers on occasion of the birth of Noah-that is, "rest" or "comfort" [Ge 5:29, Margin]. "The allusion is, undoubtedly, to the penal consequences of the fall in earthly toils and sufferings, and to the hope of a Deliverer, excited by the promise made to Eve. That this expectation was founded on a divine communication we infer from the importance attached to it and the confidence of its expression" [Peter Smith].

Matthew Henry's Concise Commentary

5:25-32 Methuselah signifies, 'he dies, there is a dart,' 'a sending forth,' namely, of the deluge, which came the year that Methuselah died. He lived 969 years, the longest that any man ever lived on earth; but the longest liver must die at last. Noah signifies rest; his parents gave him that name, with a prospect of his being a great blessing to his generation. Observe his father's complaint of the calamitous state of human life, by the entrance of sin, and the curse of sin. Our whole life is spent in labour, and our time filled up with continual toil. God having cursed the ground, it is as much as some can do, with the utmost care and pains, to get a hard livelihood out comfort us. It signifies not only that desire and expectation which parents generally have about their children, that they will be comforts to them and helpers, though they often prove otherwise; but it signifies also a prospect of something more. Is Christ ours? Is heaven ours? We need better comforters under our toil and sorrow, than the dearest relations and the most promising offspring; may we seek and find comforts in Christ.