What was the first commandment? On this there are two fascinating disagreements in Judaism. One was between Moses Maimonides (1135-1204) and the author of the Halakhot Gedolot, written in the period of the Gaonim, probably by R. Shimon Kayyara (eighth century), that for the first time enumerated in a systematic way the 613 commands. The other was between Maimonides and the poet and thinker Judah Halevi (c. 1080-c.1145). These were two different arguments, and they touched, as we will see, on fundamentals of faith.
The first is simply this. Maimonides counts the opening line of the Ten Commandments, “I am the Lord your God, who brought you out of Egypt, out of the land of slavery,” as a positive command, to believe in God. The Halakhot Gedolot does not count it as a command at all. Why not?
Nahmanides (1194-1270), in defence of the Halakhot Gedolot, speculates that its author counted among the 613 commands only the specific laws enjoining us to do this or avoid doing that. The commands are rules of behaviour, not items of faith. Faith in the existence of God, or acceptance of the kingship of God, is not itself a command but a prelude to and presupposition of the commands. He quotes a passage from the Mekhilta:
“You shall have no other gods besides me.” Why is this said? Because it says, “I am the Lord your God.” To explain this by way of a parable: A king of flesh and blood entered a province. His servants said to him, “Issue decrees for the people.” He, however, told them, “No. When they accept my sovereignty, I will issue decrees. For if they do not accept my sovereignty, how will they carry out my decrees?”
According to Nahmanides, the Halakhot Gedolot must have believed that the verse, “I am the Lord your God, who brought you out of Egypt, out of the land of slavery” is not itself a command, but a statement of why the Israelites should be bound by the will of God. He had rescued them, liberated them, and brought them to safety. The first verse of the Decalogue is not a law but a statement of fact, a reason why the Israelites should accept God’s sovereignty.
Thanks to the archeological discoveries about which I wrote in the previous Covenant and Conversation, we now know that the biblical covenant has the same literary structure as ancient near eastern political treaties. These treaties usually follow a six-part pattern, of which the first three elements were  the preamble, identifying the initiator of the treaty,  a historical review, summarising the past relationship between the parties, and  the stipulations, namely the terms and conditions of the covenant.
Seen in this context, the first verse of the Ten Commandments is a highly abridged form of  and . “I am the Lord your God” is the preamble. “Who brought you out of Egypt, out of the land of slavery” is the historical review. The verses that follow are the stipulations, or as we would call them, the commands. If so, then the Halakhot Gedolot as understood by Nahmanides was correct in seeing the verse as an introduction to the commands, not a command in its own right. That is the first disagreement.
The second was between Maimonides and Judah Halevi. For Maimonides, the first command is to believe in God, creator of heaven and earth:
The basic principle of all basic principles and the pillar of all sciences is to realise that there is a First Being who brought every existing thing into being. . . If it could be supposed that He did not exist, it would follow that nothing else could possibly exist. If however it were supposed that all other beings were non-existent, He alone would still exist. . . To acknowledge this truth is a positive command, as it is said: “I am the Lord your God” (Ex. 20:2, Deut 5:7).
Judah Halevi disagreed. Halevi was not only the greatest of medieval Hebrew poets, he also wrote one of Judaism’s theological masterpieces, The Kuzari. It is framed as a dialogue between a rabbi and the King of the Khazars. Historically, the Khazars were a Turkish people who, between the seventh and eleventh centuries, ruled a considerable area between the Black Sea and the Caspian Sea, including southern Russia, northern Caucasus, eastern Ukraine, Western Kazakhstan, and northwestern Uzbekistan.
Many Jewish traders and refugees lived there, and in 838 the Khazar King Bulan converted to Judaism, after supposedly holding a debate between representatives of the Jewish, Christian, and Muslim faiths. The Arabic writer Dimashqi writes that the Khazars, having encountered the Jewish faith, “found it better than their own and accepted it”. Khazaria thus became, spiritually as well as geographically, an independent third force between the Muslim Caliphate and the Christian Byzantine Empire. After their conversion, the Khazar people used Jewish personal names, spoke and wrote in Hebrew, were circumcised, had synagogues and rabbis, studied the Torah and Talmud, and observed the Jewish festivals.
The Kuzari is Judah Halevi’s overarching account of Judaism, cast in the form of an imagined conversation between the King and a rabbi that led to the King’s conversion. In it, Halevi draws a portrait diametrically opposed to Maimonides’ account. Judaism, for Halevi, is not philosophical but counter-philosophical. It’s not about abstract concepts but about concrete experiences: the taste of slavery, the feeling of liberation, the realisation on the part of the people that God had heard their cry and set them free. The God of Abraham is not the God of Aristotle. The prophets were not philosophers. Philosophers found God in physics and metaphysics, but the prophets found God in history. This is how Halevi’s rabbi explains his faith to the king of the Khazars:
I believe in the God of Abraham, Isaac and Israel, who led the children of Israel out of Egypt with signs and miracles; who fed them in the desert and gave them the land, after having brought them through the sea and the Jordan in a miraculous way. . . (Kuzari I:11)
He goes on to emphasise that God’s opening words in the revelation at Mount Sinai were not, “I am the Lord your God, creator of heaven and earth” but “I am the Lord your God, who brought you out of Egypt, out of the land of slavery” (Kuzari I:25). The covenant God made with the Israelites at Mount Sinai was not rooted in the ancient past of creation but in the recent past of the exodus.
What is at stake in this difference of opinion between Maimonides and Halevi? At the heart of Judaism is a twofold understanding of the nature of God and His relationship to the universe. On the one hand God is creator of the universe and the maker of the human person “in His image”. This aspect of God is universal. It is accessible to anyone, Jew or gentile. Aristotle arrived at it through logic and metaphysics. For him, God was the “prime mover” who set the universe into motion. Today, many people reach the same conclusion through science: the universe is too finely tuned for the emergence of life to have come into being through chance. Some arrive at it not through logic or science but through a simple sense of awe and wonder (“Not how the world is, but that it is, is the mystical” said Wittgenstein). This aspect of God is called by the Torah, Elokim.
But there is a quite different aspect of God which predominates throughout most of Tanakh. This is God as He is involved in the fate of one family, one nation: the children of Israel. He intervened in their history. He made a highly specific covenant with them at Sinai – not at all like the general one He made with Noah and all humanity after the Flood. The Noahide covenant is simple and basic: it involved a mere seven commands. The Sinai covenant, by contrast, is highly articulated, covering almost every aspect of life. This aspect of God is signalled by the use of the four-letter name for which we traditionally substitute the word Hashem.
Maimonides, the philosopher, emphasised the universal, metaphysical aspect of Judaism and the eternal, unchanging existence of God. Judah Halevi, the poet, was more attuned to the particularistic and prophetic dimension of Judaism: the role of God in the historical drama of the Jewish people.
Maimonides was the greatest halakhist and philosopher of the Middle Ages, but it is hard to avoid the conclusion that here, at least, the Halakhot Gedolot and Judah Halevi were closer to the plain sense of the text. Even the greatest thinker is not right all the time, which is why Judaism remains a conversation scored for many voices, each with its own insight into the infinite inflections of the Divine word.
 Maimonides, Sefer haMitzvot, positive command 1.
 Nahmanides, Hasagot to Sefer haMitzvot, ad loc. This is not Nahmanides’ own position. In his Commentary to the Torah (to Ex. 20:2), he counts the first verse of the Decalogue as a commandment in its own right, adopting a view similar to that of Maimonides.
 Mishneh Torah, Yesodei ha-Torah, 1:1-5.
 On the two aspects and names, see Kuzari IV:1-3; and Ramban to Exodus 3:13.