What is "Asherah"?
Rashi: It is a tree that is worshipped.
Why does it say "va'Ya'as Es ha'Asherah"?
Radak: He planted a tree to serve it, in addition to the Ba'al that he made.
Malbim: He served Ba'al due to his wife; her father served it. He himself made and served the Asherah.
Was there a difference between Avodah of Ba'al and of the Asherah?
Malbim: Avodas ha'Ba'al was worse. They sacrificed their children to it and did great abominations. People planted Asheros also next to Bamos on which they offered to Hashem - "Lo Sita Lecha Asher Etzel Mizbach Hashem" (Devarim 16:21). Eliyahu gathered the Nevi'im of the Ba'al and of the Asherah, but he disputed with and killed only the former (18:22, 40). Beis Yehu abolished the Ba'al, but left the Asherah (Melachim II, 13:6).
Why does it say "va'Yosef Achav La'asos Lehach'is
Radak citing Sanhedrin 102b: He wrote on the gates of Shomron 'Achav denied Elokei Yisrael.' Therefore, he has no share in Hashem (i.e. the world to come).
Why is Achav's name repeated?
Malbim: He himself decided to anger Hashem additionally (it was not due to his wife).
