English: Rashbam asks why the Torah records the lifespans of two wicked figures. He answers that the successive genealogical years establish the chronology from creation onward.
On the commentary / in context: The point is not merely Lamech’s age. Rashbam explains why the genealogy preserves even the years of figures whose personal deeds are not the focus: the numbers establish the chronology of human history.
Type of Learning: Peshat (classical commentary)What Is Learned: The genealogy’s numerical details function as a chronological framework, linking the Torah’s early history with the later biblical record.