“וַיְדַבֵּר יְהוָה אֲלֵיכֶם, מִתּוֹךְ הָאֵשׁ: קוֹל דְּבָרִים אַתֶּם שֹׁמְעִים, וּתְמוּנָה אֵינְכֶם רֹאִים זוּלָתִי קוֹל.”
“Then YHVH spoke to you out of the midst of the fire. You heard the sound of words, but saw no form (image); there was only a voice.”
Moses reminds the people the time they stood under Mount Sinai receiving the Torah.
The “sound” is the energy that comes from Binah (brain), strengthens in the lungs, and comes out as words from the mouth. The sound is the aspect of Zeir Anpin, and ‘words’ is Malchut because words manifest the inner sound.
Words depend on the inner sound and hearing depends on words.
Moses is emphasizing on the fact that they didn’t see any image but sound and words. He did that to make sure the people won’t follow any type of image of God because there’s no such thing. God has no shape or form and we should not imagine forms in our brain as the image of God.
That is the essence of the second commandment (Exodus 20:3) ““You shall not make for yourself a carved image, or any likeness of anything that is in heaven above, or that is in the earth beneath, or that is in the water under the earth.”.
When we create an image of God, or any other spiritual force in our mind, we create improper vessel for the Light and that is wrong because the Light that comes to that vessel goes to the negative side. Only the name YHVH in Hebrew letters could provide us a spiritual link to God.