Here is where many people reading Hebrews can find themselves in a dilemma. If by “rest” the writer meant “eternal salvation,” then the example of the rebellious Israelites who could not enter the Promised Land becomes gravely problematical.
Genesis chapter 10 acts as both an expansion and illustration of what Noah was prophesying
When Noah awoke and learned what had happened to him, what Ham had done to him, it isn’t Ham he curses, it’s Canaan, the youngest of Ham's four sons. I missed the significance of that the first time I read through this passage. Some commentators say this is the most remarkable prophecy in all of the Bible, showing three streams of humanity and the direction they would go, thousands of years before it happened.