משנה: (לולב) של אשרה ושל עיר הנדחת פסול.
גמרא: ושל אשרה פסול? והאמר רבא: לולב של עבודה זרה לא יטול, ואם נטל כשר. הכא באשרה דמשה עסקינן, דכתותי מיכתת. שיעוריה דיקא נמי, דקתני דומיא דעיר הנדחת. שמע מינה.
Gemara: Is then [the lulav that came from an Asherah] invalid? Did not Rava in fact say: One should not take a lulav of idolatry, but if he did nevertheless take it, it is valid?[1] Here we are dealing with an Asherah [from the time of] Moses, which was completely crushed. Its size also proves this, since it is compared with a condemned city. This is conclusive.
[1] See bHul 89a.
@General observations
In this short sugya, Rava challenges the Mishnah. The Mishnah simply states that a lulav from an Asherah, which is a tree used for idol worship, is invalid. The gemara, on the other hand, clarifies that this type of lulav was plucked off a regular palm tree (and not an Asherah) and then used in rituals connected with worship of the Goddess Asherah. Such usage also invalidates the lulav. Likewise, Rava’s statement concerning “a lulav of idolatry” can only signify one used for idol worship, as explained by Rashi.[1] This interpretation is supported by the phrases “myrtle of an Asherah” or “willow of an Asherah” in mSuk 3:2, 3, which clearly indicate that these distinct plants were merely used in Asherah rituals and could not have been plucked off of an Asherah tree.
Interestingly, usually when an amora’s statement contradicts the Mishnah, the gemara criticizes the amora. In this case, however, the gemara attacks the Mishnah. The contradiction is resolved by distinguishing between a Jewish and gentile Asherah. Rashi explains that “an Asherah of Moses” dates from the conquest of the Land of Israel in the biblical period. A lulav of such an Asherah was invalid and destroyed. Crushing such a lulav means that it no longer have the required size of four handbreadths.[2] Although a gentile Asherah is not condemned to be burned, it is rendered invalid due to its use in pagan ceremonies. Still, since it is not broken, it does have the required length and therefore Rava ruled that it is, post-factum, valid.
The gemara asserts that the discussion concerns “an Asherah of Moses” which was destroyed, by juxtaposing the phrase “lulav of an Asherah” with “lulav of a condemned city” in the Mishnah. The lulav of such a city is invalid because the city had been condemned and therefore the lulavim therein will certainly have been crushed and would not have the required height.
@Feminist observations
For a discussion of the Asherah, as a remnant of an ancient Canaanite goddess worship, see above, Mishnah 2. mSuk 3:1-5.