The reminder about Reuben losing his birthright as the firstborn son is important because that explains why sometimes in poetry and prophecy Israel is referred to as Ephraim. The reason for that is the poet doesn’t always want to use the word “Israel”; that’s not very satisfying to the creative writer, to use the same word all the time. To enjoy some variety, Israel is sometimes referred to by the name of the firstborn son. Even though history says that was Reuben, Jacob removed that honor from him and gave it to Joseph. But also recall that at that same time Jacob decreed that Joseph’s sons Ephraim and Manasseh would be reckoned as his. This effectively gave Joseph double the honor normally given to a firstborn son! So that is the reason Israel is sometimes referred to as Ephraim. When you see it in poetry or prophecy, know that the name is referring to the nation of Israel and not just the tribe of Ephraim.
These chapters tell us that the expulsion of the land’s previous inhabitants continued well into the days of the kings; Hezekiah was a later king. Also note that some of the tribe of Simeon settled in land outside of what God had promised them, and they were missed when the other Israelites were forced into exile. They were still living there at the time these genealogies were written, upon the Jews’ return from exile. This is significant because it means that this tribe was not lost as some of the other tribes were after failing to return from exile. That is a word of hope!