It is known that “The Patriarchs are truly the Divine Chariot.” I.e., their constant awareness of G-d’s unity led them to be continuously in a state of self-nullification before G-d, as was that of the prophets, including Moses. His was such a total surrender to G-dliness that the very words he uttered were Divine speech; the relation of Moses’ throat to Divine speech was that of one’s throat to his own speech.