Or HaChaim on Deuteronomy 4:12/אור החיים על דברים ד׳:י״ב

1 קול דברים אתם שומעים, "you (only) heard the sounds of words, etc." The words "the sound of words" may best be understood in connection with Shir Hashirim Rabbah on Song of Songs 1,2: "may He kiss me with the kisses of His mouth." The Midrash explains that every utterance of G'd during the revelation at Mount Sinai resulted in the creation of an angel who would stand by each Israelite and ask him: "are you willing to accept me i.e. the respective one of the Ten Commandments and what other sub-commandments it contained?" The Israelite in question would answer in the affirmative whereupon the angel would embrace him and kiss him. The words קול דברים, "the sound of the words," is a reference to these questions the angels asked the Israelites. Please refer to what I have written in Parshat Yitro (page 671) where I explained that the only words the Israelites heard from the mouth of G'd directly were the first two commandments. They were physically unable to comprehend the other eight commandments though G'd uttered them simultaneously. The other eight utterances were turned into angels. When the souls returned to the Israelites' bodies at the time, they heard those commandments from the angels. This is what the Midrash described.

2ותמונה אינכם רואים, "but you did not see an image." How can we understand Moses referring to an image by contrasting it with a sound, i.e. זולתי קול? It seems quite obvious that if one did not see an image that what one heard was only a sound? You may understand this in conjunction with what I explained on the last verse, that the Israelite saw an angel who communicated G'd's words, i.e. the sound to him. This is also a way the Mechilta explains the words: "the whole people saw the voices (Exodus 20,15)." Moses was afraid that the Israelites would think that the angel whom they had seen was the G'd of Israel. He therefore had to underline that all the Israelites saw in addition to the voices described in that verse were the angels described by the Midrash. They most certainly did not see G'd.