Mr. Sellers said that Isaac did not want Jacob to take a wife of the Canaanites, because they were involved in the seed of the race that perished during the flood. We were under the impression that everything except Noah, etc perished in the flood. This indicates that something related to a race before the flood, carried over. Is thus the way or is this not?
You are correct that everything except Noah and the other inhabitants of the ark perished in the flood. Obviously, the passengers on the ark did not include any of the cursed hybrid race of Nephilim. What Mr. Sellers is doubtless referring to is what is mentioned in Genesis 6:4, where it says:
4. There were giants on the earth in those days, and also afterward, when the sons of God came in to the daughters of men and they bore children to them. Those were the mighty men who were of old, men of renown.
That little phrase “and also afterward” is very important. It tells us that, though that cursed race of giants was wiped out by the flood, yet afterward another outbreak occurred wherein after the flood once again the sons of God came in to the daughters of Adam and they bore children to them. This resulted in another outbreak of this race of giants, known this time as the “Rephaim.”
Therefore it was the children of this later outbreak who were mixed up with the Canaanites, and not those who had perished in the flood. It was the same hybrid race as before the flood, but not the same individuals, since they had perished. This time, God wiped them out using the sword of Israel and of the other, Shemite nations around Israel. At some point, the angels who thus sinned were cast into prison, and no longer are free to trouble the earth (II Peter 2:4). Therefore, we need not fear another such occurrence in our day.
I pray that helps. Thanks for the great question.