Genesis 5:32

And Noah was five hundred years old
Or "the son of five hundred years" ^F6; he was in his five hundredth year: it can hardly be thought that he should live to this time a single life, and have no children born to him, which he might have had, but were dead; though some think it was so ordered by Providence, that he should not begin to procreate children until of this age, because it being the will of God to save him and his family from the flood, had he began at the usual age he might have had more than could conveniently be provided for in the ark; or some of them might have proved wicked, and so would deserve to perish with others: and Noah begat Shem, Ham, and Japheth;
not together, but one after another; and since Ham was the younger son, see ( Genesis 9:24 ) and Shem was an hundred years old two years after the flood, ( Genesis 11:10 ) he must be born in the five hundred and second year of his father's age; so that it seems most probable that Japheth was the eldest son, and born in the five hundred and first year of his age; though Shem is usually mentioned first, because of his superior dignity and excellency, God being in an eminent manner the God of Shem, ( Genesis 9:26 ) and from whom the Messiah was to spring, and in whose line the church of God was to be continued in future ages. The name of Japheth is retained in Greek and Latin authors, as Hesiod ^F7 Horace {h}, and others ^F9, by whom he is called Japetos and Japetus.