Genesis 9:18 - Coke's Commentary on the Holy Bible

The sons of Noah, &c.— Japheth, though named last, was, as we have before observed, the eldest of Noah's sons, as appears from ch. Genesis 10:21. Shem, whom some would make the eldest, appears, says Shuckford, to have been two years younger than Japheth; for Noah was five hundred years old at the birth of his eldest son, that is, a hundred years before the flood. See Genesis 5:32 compared with Genesis 7:6. But Shem was but a hundred years old two years after the flood, namely, at the birth of Arphaxad, ch. Genesis 11:10. and consequently he must have been two years younger than Noah's first-born. Canaan, the son of Ham, is mentioned here to introduce the following account, in which the origin of that people is marked out, who became so detestable afterwards, as to be destroyed for their enormities by the hand of the Israelites, under the immediate direction of God.