What does Genesis 5:25 mean?

The prior verses, describing the life of Enoch, were an unusual break from the normal pattern of this passage. Enoch is said—twice—to have "walked with God," indicating a deep and obedient relationship. Then, unique among all the men of this genealogy, Enoch is not given the summary phrase "and he died." Rather, he is taken by God prior to his natural death. This occurs at the relatively young age of 365 years, making Enoch's life the shortest recorded in this chapter. Interestingly, the shortest life recorded in Genesis chapter 5 is that of the father of the longest life recorded in the entire bible: his son, Methuselah.

Here, in verse 25, the genealogy resumes its normal pattern. Enoch's son, Methuselah, fathered his son Lamech at the age of 187 years old. It's important to note that this Lamech, though he shares the same name as one of Cain's descendants, is not the same man. The man described as a murderer with two wives (Genesis 4:23–24), Lamech's lineage was through Cain, Enoch (also not the same as the Enoch of this chapter), Irad, Mehujael, and Methushael (Genesis 4:17–18). Then, as now, most people were given names similar or identical to those others already had.

However, this common name also creates in interesting contrast. Cain's descendant will revel in his own sin, while Seth's descendant will mourn over the suffering caused by the fall of man (Genesis 5:29).