The Calvinist is always fixated on their Platonic ideas about God. As such, any time the Bible makes simple pronouncements, those have to be reinterpreted in light of the Platonic understanding of God. When the Bible says that God speaks, this violates God’s timelessness and His immutability (along with a host of other Greek attributes). After all, a God outside of time could not enter time (because to the Platonist that would make God susceptible to change). Entering time and speaking successive words also is a clear cut sign that something is not immutable. Augustine handles this by saying that when the Bible mentions God’s speaking, it is a creature in time uttering the words:
But how didst thou speak? Was it in the same manner in which the voice came from the cloud saying, “This is my beloved Son”? For that voice sounded forth and died away; it began and ended. The syllables sounded and passed away, the second after the first, the third after the second, and thence in order, till the very last after all the rest; and silence after the last. From this it is clear and plain that it was the action of a creature, itself in time, which sounded that voice, obeying thy eternal will. And what these words were which were formed at that time the outer ear conveyed to the conscious mind, whose inner ear lay attentively open to thy eternal Word. But it compared those words which sounded in time with thy eternal word sounding in silence and said: “This is different; quite different! These words are far below me; they are not even real, for they fly away and pass, but the Word of my God remains above me forever.”
This is the kind of fallback position that Calvinists must assume when confronted with the clear text of the Bible. If the text says “God said this or that” then it means “an unmentioned parrot creature said this or that”.