The Gemara's Drashah hinges on the 'Vav' in "Eleh Elohecha... Asher He'elucha" (אלה אלהיך... אשר העלוך; "these are your gods... who brought you up"). Why then, does Nechemiah 9:18 record the declaration as "Zeh Elohecha... asher he'elcha" (זה אלהיך... אשר העלך; "this is your god... who brought you up"), omitting the 'Vav' upon which the Gemara's interpretation is based? (Pesach Einayim of the Chida)

Ben Yehoyada #1: Most of the people used the wording recorded in Shemos, "Eleh... Asher He'elucha." This implied, chas veshalom, that there was another power in addition to Hash-m. According to the opinion of Acheirim in our Gemara, this is a less severe form of idolatry than attributing the Exodus solely to another power. The more severe view was held by a minority, as reflected in the Pasuk in Nechemiah, "Zeh... Asher He'elcha." When Hash-m recounted the sin in Shemos, He cited the formulation used by the majority, since the Tzibur was judged accordingly. Nechemiah, however, emphasizes Hash-m's kindness: even though some denied Hash-m completely, He nevertheless spared the nation.

Ben Yehoyada #2: The two Pesukim reflect the distinction between thought and speech. The Pasuk in Nechemiah refers to their inner belief: they thought, chas veshalom, that the Golden Calf alone was the true power. The Pasuk in Shemos records their spoken declaration, which was milder, attributing power both to Hash-m and to the Calf. Hash-m spared them because of their less severe expression, despite the greater severity of their thoughts. This is alluded to in Eichah (5:17): "For this (zeh) our heart has become faint; for these things (eleh) our eyes have grown dim." "Zeh" alludes to "Zeh Elohecha" in Nechemiah and is associated with the heart, i.e., their thoughts. "Eleh" alludes to "Eleh Elohecha" in Shemos and is associated with the eyes, i.e., their outward expression.

Anaf Yosef: The Pasuk in Nechemiah reflects what the Erev Rav truly intended - pure idolatry: "Zeh Elohecha Yisrael Asher He'elcha" without the vav. But since Klal Yisrael would not have accepted outright idol worship, they could not present it that way when persuading them. Therefore, in Shemos it is recorded in the more acceptable form they used, "Eleh...Asher He'elucha," with the Vav, which implies 'Shituf'.

According to Acheirim, Yisrael were spared destruction because they believed in the Calf together with Hash-m, as implied by the plural "who brought you up." But why should this help? Isn't associating another deity with Hash-m (Shituf) just as much idolatry as worshipping idols alone? (Rosh Yosef)

Rosh Yosef (by Rav Yosef ben Yaakov of 17th-18th Century Pinczow-Poland): The Midrash Shocher Tov (Parsha 8) states that at Matan Torah, Klal Yisrael responded to the commandments as they were given. The Zohar (Tikunei Zohar 32, 76a) teaches that "Anochi Hash-m Elokecha" and "Lo Yihyeh Lecha Elohim Acherim" were said simultaneously. Since they were said together, Klal Yisrael gave only a single response, which functioned as an acceptance of "Anochi." "Lo Yihyeh" was not separately affirmed with its own distinct "no", but was included in that same response. The Rosh Yosef suggests that this is the key to the Gemara. Had Yisrael later declared that the Golden Calf alone brought them out of Egypt, they would have been directly denying "Anochi," the command they had explicitly accepted at Sinai. Instead, by saying, "These are your gods who brought you up from Mitzrayim", they left room for an interpretation of 'Shituf' - attributing the Exodus both to Hash-m and to the Calf. Although this remains idolatry and violates "Lo Yihyeh," it is not a denial of the specific acceptance of "Anochi." Therefore, the letter vav in "he'elucha" spared them from total destruction, because it allowed their statement to be read as a violation of "Lo Yihyeh" without constituting a rejection of "Anochi," which was the command they had explicitly accepted at Sinai.

What is the rationale behind the permission given by R. Yochanan to mention the name of any idolatry mentioned in the Torah?

Sefer She'eltos (Rav Achai Gaon) (cited in Rinas Yitzchak - Yishaya 46:1): 'Once it was permitted, it remains permitted', meaning that since it is permitted to mention those names while reading from the Torah, it is permitted even in other situations.

Sefer Yereim (Ibid.): The Torah would not mention the name of an idol unless its status had already been nullified. Therefore, the very fact that the Torah records its name indicates that it may be mentioned, just as the Torah itself mentions it.

Chida (Maris haAyin): The fact that the Torah records the name of an idol indicates that a "spark" of holiness remains within it. In fact, by mentioning the name, that spark is separated out and elevated.

What was the Gemara adding by bringing this story, since it had already established beforehand that after they worshipped idols, they became attached to it?

Aruch LaNer: The Gemara had assumed that this would not apply to a child and if they would not have had a desire for it, a child would not have become attached to it. The story of the child disproves that.

How did the Gemara know that the child had never been taught 'Kriyas Shema'? Perhaps he had learned it and personally rejected it?

Maharsha: If his father would have consistently taught it to him, fulfilling his Mitzvah to educate his child in Torah, the child would not have rejected it and said, 'Hush'.