The study of page 45 of Gemara Avoda Zara begins with a Mishnah that establishes a fundamental distinction regarding natural landmarks used for idol worship. The Mishnah teaches that if gentiles worship mountains or hills, the landmarks themselves remain permissible for use. This is based on the principle that one cannot render something forbidden that is naturally attached to the ground. However, any objects or idols placed upon these mountains are strictly forbidden. This ruling is derived from the verse that commands one not to covet the silver and gold found upon them; while the precious metals on the mountain are prohibited, the mountain itself is not.
Rashi clarifies the practical application of this law, explaining that "permissible" means a person is allowed to quarry stones from such a mountain or plant crops upon it. The logic is rooted in the scriptural phrasing "their gods upon the mountains," which implies that the deity is a separate entity situated on the mountain, rather than the mountain itself being the deity. Even in a case where the mountain has been plated with gold or silver, Tanna Kamma maintains that this plating is forbidden. Although the mountain is not an object of idol worship, a scriptural decree dictates that any detached or added item on the mountain carries the same status as a detached idol.
This distinction leads to a unique legal paradox regarding sacrifices. If a person slaughters an animal as a sacrifice to a mountain, the animal does not become forbidden as a "sacrifice to the dead." Since a mountain cannot legally become an idol, the sacrifice offered to it does not take on the prohibited status of an idolatrous offering. Nevertheless, the individual who performs this act is still liable for the death penalty. Even though the object of their worship cannot become forbidden, their intent to serve an idol is sufficient to convict them.
Rabbi Yose HaGelili provides further scriptural support for this view, noting that the Torah specifies "their gods upon the mountains" and "their gods upon the hills," emphasizing that the gods are on the landmarks, but the landmarks are not the gods. This raises a question regarding the Asherah tree. If items attached to the ground cannot become forbidden, why is an Asherah tree prohibited? The Mishnah explains that the Asherah tree is different because it involves human handiwork. A person must plant a tree, whereas no human plants a mountain. Because a human being has a direct physical connection to the planting and existence of the tree, it can become forbidden through worship.
Rabbi Akiva offers an additional perspective on the verses describing idols "under every leafy tree." He explains that these descriptions were not meant to limit the prohibition to what is under the tree while excluding the tree itself. Rather, they served as geographical markers. When Moshe Rabbeinu instructed the Jewish people as they prepared to enter the Land of Israel, he gave them these signs so they would know exactly where to search for and destroy the hidden idols of the local populations. Therefore, the tree itself can certainly be forbidden, as evidenced by the explicit command to burn such trees in fire.
The Gemara seeks to identify the specific point of disagreement between the Tanna Kamma and Rabbi Yose HaGelili. Reish Lakish suggests that their dispute concerns the status of a mountain's plating. The Tanna Kamma believes that gold or silver plating is considered an addition "upon" the mountain and is therefore forbidden. Rabbi Yose HaGelili, however, argues that the plating becomes nullified to the mountain; just as the mountain is permissible, the plating becomes permissible as part of the mountain's structure. Rav Pappa offers a different interpretation, suggesting that both agree plating is forbidden. Instead, they argue over a tree that was originally planted for a neutral purpose, such as shade, and was only later worshipped as an idol. The Tanna Kamma holds that such a tree remains permissible because its initial status was not idolatrous. Rabbi Yose HaGelili and Rabbi Yose bar Rabbi Yehuda disagree, maintaining that once a tree is worshipped, its status changes and it becomes forbidden regardless of its original purpose.
The discussion then turns to the practical process of purging idol worship from the land. Rabbi Yehoshua ben Levi explains that there are two distinct stages of destruction. Upon first entering the land, the people were commanded to perform a "cutting" of the idolatrous trees. This initial act was meant to be done immediately to allow the conquest to proceed. Only after the land was fully conquered were they required to return and completely uproot the roots. This ensures that the influence of the idol is thoroughly erased from the earth. Rabbi bar Chama and other sages discuss how this multi-stage process is hinted at in the double language of the biblical command to "surely destroy" these items.
Finally, the Gemara addresses the requirement to "destroy the name" of idolatrous sites. Rabbi Eliezer and Rabbi Akiva explain that this involves more than physical destruction; it requires changing the names of these places to something derogatory to express loathing for the idol. If a place was called Beit Galya, meaning the "High House," it should be renamed Beit Karya, the "Low House." Similarly, if a site was known as Ein Kol, the "Eye of All," it should be referred to as Ein Kotz, the "Eye of the Thorn." By altering these names, the memory of the idol is not only removed but replaced with a reminder of its disgraceful nature.