Charles Ellicott Commentary Genesis 5:32

"And Noah was five hundred years old: And Noah begat Shem, Ham, and Japheth." — Genesis 5:32 (ASV)

Noah was five hundred years old. —No reason is given why Noah had no son until he had reached such an advanced age; nor, in fact, does it mean that he could not have had other sons, though they were unworthy of sharing his deliverance. It is remarkable also that neither of the three sons who were with him in the ark had offspring until after the flood. (See Genesis 11:19.) From them have sprung the three great lines into which the human family is divided.

Shem means name: that is, fame, glory; and he, as the owner of the birthright, was the progenitor of our Lord. Ham, the dark-coloured, was the ancestor of the Egyptians, Cushites, and other dark-skinned peoples of Arabia and Africa. Japheth, the widener, but according to others the fair, though the youngest son, was the ancestor of most of the peoples of Europe, as well as of some of the chief nations of Asia.