Recently, we celebrated the holiday of Chanuka. This holiday honors the Hasmoneans who recovered and rescued our Beit HaMikdash from the Greeks. The Hasmonean family was a great generation without whom the Torah wouldn't have continued to be studied and practiced. Despite their success in the field of Torah learning and their success as rulers, the whole family was almost completely killed out by their enemies, and the rest were sold into slavery. Why was such a powerful and helpful family of Jews wiped out?
The Ramban asserts that the answer lies in this weeks Parsha. The Pasuk states, שבט מיהודה לא יסור, "The scepter should never depart from Yehudah...(בראשית מט:י). The Hasmonean family were descendants from the tribe of Levi, and they were Kohanim. This means they were not from the tribe of Yehudah, to whom Hashem and Yaakov promised leadership of the Jews. This author wishes to add that the Hasmonean family's actions were particularly bad since they saw what happened in the kingdom of Yisrael (the ten northern tribes) where all the kings were descendants other than Yehudah, and the kingdom was eventually destroyed. Since that kingdom was destroyed, the Hasmoneans should have used that as a warning to be extra careful to follow the laws of the Torah, and could have avoided annihilation and reduction to the status as slaves.