When the Torah was given on Shavuot, and Bnei Yisrael were gathered at the foot of Har Sinai, they heard ten utterances. The Torah teaches (Shemot 20:1) that “Elokim spoke all these words,” but we understand that the encounter was with the same Divine Presence that had told Moshe a year earlier that he would return to this place – which is explicitly identified there with the four-letter Name that we commonly refer to as “Hashem.”
So, we find that in association with the giving of the Torah at Har Sinai, there are two different names being used to identify the Giver. The first, as we saw from Parshat Yitro, is “Elokim,” traditionally associated with the Divine attribute of Justice and with the assertion of natural law. On the other hand, the name that was revealed to Moshe a year earlier, comprised of four letters, is associated with Divine Mercy.
The first of the ten utterances that Bnei Yisrael heard on Har Sinai begins, “I am Hashem who took you out of Mitzrayim,” and we know that the exodus from Mitzrayim was affected principally through the revelation of the four-letter Name. Later, at the end of Moshe’s life when he recounts these events, he relates the same ten utterances and says that they were spoken by Hashem (Devarim 5:19).
Of course, we know without a doubt that Hashem is One and His Name is One – and thus there is no question as to who spoke to Israel from out of the flame (ibid. 4:12) – but there is a question as to the mechanism by which the message was communicated and how it was experienced by all of us at Har Sinai. This is a very difficult and complex matter, one that Rabenu Bachye attempts to unravel, and we will only be able to scratch the surface here.
As is often the case with spiritual matters in the Torah, there is a notable dispute between Rambam and Ramban over the question referenced by Rabenu Bachye. Rambam teaches in Moreh Nevuchim that when Hashem spoke the first two utterances, the experience of Moshe and of Bnei Yisrael was profoundly different due to their relative levels of spiritual attainment and prophecy. For Bnei Yisrael, it was a terrifying experience; they felt it would surely destroy them physically, so they begged Moshe to make it stop and to relate the rest of the words to them once he had heard them from Hashem. According to this reading, only the first two utterances were heard by Bnei Yisrael directly from Hashem and the rest were spoken to them by Moshe. Ramban disagrees with this interpretation. He says that Israel heard all of the words (possibly at once) and that this is attested to by other sources in Scripture. However, they were only capable of comprehending the first two – they heard those utterances with their ears and listened with their hearts. With the remaining eight, they heard, but did not understand until Moshe explained their meaning.
Thus, the narrative in the Torah relates events from the perspective of Bnei Yisrael – that Elokim spoke to them – because this was the extent of their understanding. It is equivalent to Hashem speaking from within the flame, which Moshe would later relay, or from out of the clouds and the darkness. This means that the constraints of physicality placed upon our faculties of perception mediated between the source of the message and our reception of it. Moshe and Bnei Yisrael heard the same message, but Moshe understood that this was the Presence that had been revealed to him as the four-letter Name, Hashem, because his prophecy came through a clear lens (Yevamot 49b). This contrasts with our forefathers, to whom this name was not revealed; rather, they experienced Him as Kel Sha-kai (Shemot 6:3). Bnei Yisrael, on the other hand, at the level of prophecy available to them at Har Sinai, perceived Elokim speaking.