Gemara

Question: What is the source that the verses ("everything Hash-m commanded...") discuss idolatry?

Answer #1 (D'Vei Rebbi - Beraisa): It says "that Hash-m spoke to Moshe", and "that Hash-m commanded you through Moshe." The Mitzvah that Yisrael heard Hash-m say and was explained through Moshe is idolatry.

(Tana d'Vei R. Yishmael): Yisrael heard "Anochi (Hash-m Elokecha)" and "Lo Yihyeh Lecha (other gods in front of Me)" from Hash-m.

Answer #2 (d'Vei R. Yishmael - Beraisa): "From the day that Hash-m commanded" - the first Mitzvah Yisrael received was idolatry.

Rejection: Yisrael received 10 Mitzvos at Marah!

Makos 23b (R. Simlai): Moshe received 613 Mitzvos.

(Rav Hamnuna): He learns from "Torah Tzivah Lanu Moshe" - the Gematri'a of Torah is 611. Additionally, Yisrael heard two Mitzvos directly from Hash-m - "Anochi..." and "Lo Yihyeh Lecha."

Rishonim

Rambam (Sefer ha'Mitzvos, Aseh 1): The first Mitzvah is to believe in G-d, that there is a cause that does everything in the world - "Anochi Hash-m Elokecha." It is clear from Makos that Anochi is one of the 613 Mitzvos.

Ramban (Sefer ha'Mitzvos Aseh 1 and Lo Sa'aseh 5): Bahag does not count Emunah in Hash-m among the 613. "Lo Yihyeh Lecha" includes several Lavim - not to own idols, make idols, bow to them or serve them. If so, Yisrael heard five Mitzvos from Hash-m, and only 608 from Moshe! Bahag holds that Hash-m commanded 613 matters for Yisrael to do or refrain from. Emunah in Hash-m is the basis for the Mitzvos, so it is not counted among the 613. Bahag must hold that "Lo Yihyeh Lecha" includes two Lavim - 1) Not to own or make idols, and 2) Not to bow to them or serve them. The Mechilta supports this. However, the Mechilta connotes that Anochi is a Mitzvah, i.e. to accept Hash-m's kingship and persevere in Emunas Hash-m. It gives a parable of a nation that asked a king to make decrees on them. He said 'after you accept my kingship, I will make decrees on you.' Makos 24a counts Lo Yihyeh Lecha like one Lav against Avodah Zarah.

Tashbatz (1:139, cited in R. Akiva Eiger 8b): Why did the Ramban need to rely on mere reasoning, why he himself rejects, to defend Bahag? Horayos 8a explicitly says that Anochi is not counted among the Mitzvos! D'Vei R. Yishmael taught that the first Mitzvah Yisrael received (in the 10 utterances) was idolatry, i.e. Anochi is not a Mitzvah. Surely Bahag relied on this. He would not rely on mere reasoning to reject the simple reading of Makos 24a, which connotes that Anochi is a Mitzvah. The reason to omit Anochi is like the Ramban said, that it is the basis for all Mitzvos. One who does not acknowledge Hash-m has no Mitzvos at all! Also, Mitzvos are decrees of the King. Accepting the yoke of His kingdom is not a Mitzvah. Rather, it leads to Mitzvos! The parable in the Mechilta connotes that accepting the king's authority is not considered one of his decrees. How can the Ramban explain oppositely?! Surely, what I said is Bahag's source, but it is not a solid proof. Perhaps idolatry is included in Anochi - I am Hash-m Elokecha, and no other is your god. However, if so one who denies G-d would be liable to bring a Korban (based on the Sugya in Horayos), even if he did not serve idolatry!

Note: This question is based on R. Akiva, who obligates a Korban even without an action (Krisos 3b). Perhaps d'Vei R. Yishmael holds like Chachamim, who obligate a Korban only for a Lav with an action!

Tashbatz (ibid.): Even though d'Vei R. Yishmael was rejected, we cannot say that he had a pathetic reasoning to obligate a Korban for one who (denied Hash-m, but) did not serve idolatry. Also, this reasoning dictates that one who acknowledges Hash-m would be exempt if he served idolatry, for he admits to the first Mitzvah (from which we derive the Isur of idolatry). This is clearly wrong. Also, we cannot derive a Lav of Avodah Zarah from an Aseh fulfilled by doing something. We derive a Lav from an Aseh to be like an Aseh, but not to be a Lav. Perhaps Anochi and Lo Yihyeh Lecha are one matter, to accept that Hash-m is G-d and abandon anything else. If so, the second utterance is Lo Sa'aseh Lecha, the Isur to make idols. Not bowing and serving them are details of Lo Yihyeh Lecha, and they are not counted (by themselves). A support for this is Zachor (Es Yom ha'Shabbos Lekadsho). It is surely one of the utterances, and it includes a Lav (Shamor) and an Aseh. The utterances are not divided (counted) like the Mitzvos included in them. The Torah calls them 10 utterances, and Chachamim said that Anochi and Lo Yihyeh Lecha are two of them. There are (at least) nine other Mitzvos, for Shabbos includes a Lav and an Aseh. If Anochi and Lo Yihyeh Lecha are one, the Korban is for the Lav. However, the Gemara says that there are only two Mitzvos in them. If so, we must say that Lo Sa'aseh Lecha is the next utterance. If so, it must be a Mitzvah, and if so Yisrael heard three Mitzvos from Hash-m, and there would be 366 Lavim in all, unlike R. Simlai.

Note: Seemingly, if we say that Lo Sa'aseh Lecha is a separate utterance, we did not hear it from Hash-m! Also, perhaps R. Simlai holds like Chachamim, unlike d'Vei R. Yishmael, who was rejected. Also, even if d'Vei R. Yishmael must hold that there are 614 Mitzvos, why must he say that there are 366 Lavim? Perhaps he adds an extra Aseh!

Tashbatz (ibid.): Also, it is difficult to say that Lo Yihyeh Lecha is part of Anochi, and Lo Sa'aseh Lecha is a separate utterance. Rather, Anochi and Lo Yihyeh Lecha are two utterances containing two Mitzvos, either one Mitzvah in each or both are in Lo Yihyeh Lecha. Even if we say the first way, (regarding Korbanos) Avodah Zarah is called the first Mitzvah, for Korbanos are only for Lavim. It is primary to explain like Bahag, that Anochi is not a Mitzvah.

Rebuttal (Megilas Esther on Aseh 1, DH v'Nir'eh): Rashi (8b DH l'Min) says that idolatry is mentioned at the beginning of the 10 utterances, Anochi and Lo Yihyeh Lecha, i.e. idolatry. Why did he mention Anochi? He was bothered, for the first Mitzvah is Emunas Elokim! He answers that even though Anochi is the Mitzvah of Emunah, it includes idolatry, for not believing in Hash-m is like serving idolatry. Alternatively, we said that idolatry was said at the beginning. We did not say that it is first. Rashi mentions Anochi, lest one think that idolatry is the first Mitzvah. However, the Gemara connotes that at the beginning and first are the same. Zohar ha'Raki'a (the Tashbatz) says that the Gemara proves that Anochi is not counted. He did not scrutinize Rashi's words. Even though it is a foundation, it is also a Mitzvah to believe in this foundation. The Mechilta means that accepting the king's authority is not a Mitzvah before they accept it, but afterwards it is a Mitzvah! We need not say that Yisrael heard all the Lavim included in Lo Yihyeh Lecha from Hash-m. However, the Gemara explained that Yisrael heard two Mitzvos from Hash-m. If one of them was "do not bow to idols", the Gemara should have brought this explicitly!

Rebuttal (Malbim Shmos 20:4): We cannot say that Yisrael heard only part of Lo Yihyeh Lecha from Hash-m. If so, there are 11 utterances! Also, the Medrash explicitly says that the opinion that Yisrael heard only two utterances holds that then they told Moshe "we will hear from you." If Moshe taught to Yisrael "Lo Sa'aseh Lecha..." surely there are 11 utterances! The question was not difficult. The three Lavim of making idols, bowing and serving idolatry are included in the the seven Mitzvos of Benei Noach. Moshe already taught these at Marah, like it says in Horayos.

Question (Sefer ha'Ikarim 1:14): If Anochi is a Mitzvah, why aren't the other principles of belief counted like Mitzvos?

Drashos ha'Ran (9 DH v'Hu): Do not say that Anochi, the first Mitzvah, is to believe that Hash-m is the first cause and does everything. The verse does not suggest this at all, even though it is included in it. Rather, it is a Mitzvah to believe in Torah from Shamayim. It does not come as a Mitzvah, rather, something known that they already admit to. The Chidush is that He is Elokecha, who leads you. This is why it says "who took you out of Mitzrayim." Man's innate intellect dictates that Hash-m's must exist. One cannot deny this. Anochi teaches that He gives us the Mitzvos.

Abarvenel (Shmos 20 DH ha'She'alah ha'Zayin): R. Chasdai says that there cannot be a Mitzvah to believe in Hash-m, for Mitzvah applies to matters for which there is desire and choice, but not to belief. This is primary. Semag and the Ran say that Anochi is a Mitzvah to believe that the One who gave us the Torah through Moshe is the One who took us from Mitzrayim. This is difficult, for this is the eighth principle of our creed. Why is the eighth principle the first Mitzvah?! Further, the second and third utterances are the second a third principles! Semak says that the first Mitzvah is to believe that the One who created the world rules above and below and over the four corners of the world and conducts every occurrence. The Kuzari says that in Anochi it does not say that Hash-m created the world, for Hash-m told to Yisrael what they saw.

Poskim

Bi'ur Halachah (1:1 DH Hu, from Sefer ha'Chinuch): There are six Mitzvos that one can fulfill constantly. One is to believe that there is one G-d who caused everything to be. All that is, was and will be is due to His will. He took us out of Mitzrayim and gave to us Torah - "Anochi..."