What is the meaning of "k'Daber Efrayim Reses"?
Rashi: When Yaravam had Kin'ah for Hashem, and spoke harsh words against Shlomo, it was with trembling, for Shlomo was a great king.
Rashi citing Targum Yonasan: When one of Efrayim spoke, trembling gripped the nations 1 .
Malbim: When the king of Efrayim said to serve the calves, there was trembling.
Radak: I.e. the nations around Efrayim.
Why does it say "Nasa Hu b'Yisrael"?
Rashi: Due to this, Yaravam merited to be king of Yisrael.
Targum Yonasan: [Efrayim] ruled over Yisrael 1 .
Malbim: [When Melech Efrayim said to serve the calves, there was trembling.] He feared lest the nation ascend to Yerushalayim and return to their masters (Melech Yehudah), and kill him.
Radak. It was the highest Shevet - "v'Zaro Yihyeh Melo ha'Goyim" (Bereishis 48:19).
How was he guilty with Ba'al?
Rashi: Once he rose to grandeur, he was guilty of idolatry.
Malbim: Even though Efrayim served amidst coercion of trembling and fear, they were liable for Ba'al 1 , and were punished and killed.
One who is coerced to serve idolatry must refuse even if he will be killed for this. Or, perhaps they were coerced to serve the calves, but they willingly served Ba'al. (PF)
What do we learn from "va'Yamos"?
Rashi: Beis Yaravam and Beis Achav were wiped out.
Radak, based on Targum Yonasan: After [Efrayim] were liable for serving idolatry, they were stricken in front of their enemies, as if they died.
Malbim: Refer to 13:1:3:2.
