These are the generations of Shem,.... Or a genealogy of the posterity of Shem; not of all of them, only of those of the line which led to Abraham, by which might appear the true line in which the Messiah from Adam through Abraham sprung:
Shem was one hundred years old, and begat Arphexad two years after the flood; by which it is pretty plain that he was younger than Japheth; Genesis 10:21 of Arphaxad his son,