Following the destruction of the second Temple, the house belonging to King Yannai was abandoned and fell into disrepair. Ultimately, pagans entered the house and placed an idol dedicated to Mercury in it. Later on, other non-Jews who did not believe in Mercury as a deity removed the stones from the building and used them to pave the paths and streets of the city.
This led to a disagreement among the Sages. Some of them refused to walk on the newly paved streets, lest they benefit from the stones that had been consecrated to the worship of Mercury. Others had no such compunctions and walked on them without concern. Rabbi Yoḥanan ruled: The “son of holy ones” – referring to Rabbi Menaḥem the son of Rabbi Simai – walks on these streets, how can we do otherwise?
The Gemara explains that Rabbi Menaḥem the son of Rabbi Simai was referred to in this way because he would refrain from even looking at the idolatrous images stamped on coins.
The Gemara explains that the reasoning behind refraining from walking on the stones followed the opinion of Rav Giddel quoting Rav Ḥiyya bar Yosef in the name of Rav who taught that the passage in Sefer Tehillim 106:28 should be interpreted to mean that any contribution made to avoda zara remains forbidden forever. Those who disagreed believe that only a contribution that parallels a halakhic sacrifice will become forbidden in that way.
The idea that any contribution made to avoda zara remains forbidden forever is grounded in a Biblical passage, but a number of explanations have been put forward to rationalize it. The Meiri argues that since such a contribution is viewed as similar to a sacrifice, just as sacrifices remain consecrated forever, so these contributions are, as well. The Maharal is quoted as saying that such a contribution is more problematic than an idol, since the idol is not actually a god, but is only the representation of the deity; a contribution, however, which was actually consecrated to the god itself, remains forbidden forever.