The Days of Adam (Gen 5:4–5)

The Genealogy of Adam

⁴ The days of Adam after he fathered Seth were 800 years …

וַיִּֽהְי֣וּ יְמֵי־אָדָ֗ם אַֽחֲרֵי֙ הוֹלִיד֣וֹ אֶת־שֵׁ֔ת שְׁמֹנֶ֥ה מֵאֹ֖ת שָׁנָ֑ה

It’s not utterly uncommon to call a person’s age his “days” and then present the number of years. (They never really give anyone’s numerical age in days.) In the pattern that will be established in vv. 6–8 — which will already be followed, for Adam, in v. 5 — everyone’s age at death will be called “all [So-and-So’s] days.”

This part of the pattern, however — the amount of time the person lives after fathering his first child — is not called his “days” for anyone else in the chapter. I haven’t found any commentary or translation that even acknowledges this difference. NJPS, for one, simply normalizes it — or ignores it — and says “Adam lived 800 years,” as they do in the rest of the chapter.