How did the 12 sons of Jacob become the 12 tribes of Israel?
The covenant promise passed from Abraham to Isaac to Jacob, and Jacob's twelve sons—including Joseph—went down to Egypt because of grain. While they and their families were in Egypt, they exploded in population, and those twelve sons became the twelve tribes of Israel, later led out by Moses and into the land by Joshua.
Les explains that after Abraham received the covenant promise that a nation would come out of him, the next person in response was Isaac, then Jacob. Out of Jacob came the twelve sons, one of whom was Joseph. Because of Joseph, those twelve sons ended up in Egypt due to the grain. While the twelve sons and their families were in Egypt, they exploded in population. Those twelve sons therefore became the twelve tribes of Israel, which Moses led out, took through the wilderness, and Joshua led into the land. Les notes that many people have not been taught these basic fundamentals.