And Adam knew his wife again; and she bare a son, and called his name Seth: For God, said she, hath appointed me another seed instead of Abel, whom Cain slew. – Genesis 4:25 ...

The intent of chapter 5 seems to emphasize the genealogy of Seth rather than that of Adam. We already were given Cain’s genealogy in chapter 4. Perhaps God revealed to Adam that Seth’s line would ...