What are "Eilim"?
Rashi: This is an expression of Elah (Bereishis 35:4). It is an elm tree.
Radak: This is like Ilanim (trees), like "ha'Nechamim ba'Elim", "Eilei ha'Tzedek" (57:5, 61:3).
Why did they desire the trees?
Rashi: They wanted to serve idolatry under them - "[Yizbechu
Why does it say "Yevoshu" (third person) and "v'Sachperu" (second person)?
Radak: Verses often switch like this, e.g. "Shim'u Amim Kulam" (Michah 1:2), "Tashuvu u'Vo'u Na" (Iyov 17:10).
Why did they choose the gardens?
Rashi: They served idolatry there - "ha'Miskadeshim veha'Mitaharim El ha'Ganos" (66:17).
Malbim: Some served idolatry because their senses and desire misled them to think that the Elim were Divine matters. Others chose to do so from intellect, for they thought that idolatry can help and harm. They put the idols in the gardens, so that the influence and Brachah from Shamayim for dew and rain would come on their gardens. The latter were worse, for the sin was via intellect and choice. Therefore, they will have Cherpah, a greater shame than Bushah 1 .
Malbim (Yirmeyah 51:51): Bushah is shame that one himself feels, Kelimah is shame from others, and Cherpah is due to a matter.
After the first Churban, Yisraelim did not serve idolatry in gardens and "v'Sachas Kol Etz Ra'anan" (Devarim 12:2)!
Radak: The last three verses of this Parashah do not refer to Yemos ha'Mashi'ach. It mentions idolatry regarding Bayis Rishon, for it discusses eradication of sinners, for idolatry and other sins. This will be before Yemos ha'Mashi'ach. After the first Churban, they saw that Asherim did not save them from the enemy that destroyed and exiled them. Then they will be ashamed, and know that their service of idolatry was Sheker. Therefore 1 , there were no idolaters in Yisrael in Bayis Sheni.
Sanhedrin 64a implies that Yisraelim still served idolatry after the Churban, until Chachamim prayed to abolish the Yetzer ha'Ra for it, and Hashem agreed! (PF)