John Calvin Commentary Isaiah 29:4

"And thou shalt be brought down, and shalt speak out of the ground, and thy speech shall be low out of the dust; and thy voice shall be as of one that hath a familiar spirit, out of the ground, and thy speech shall whisper out of the dust." — Isaiah 29:4 (ASV)

Then shalt thou be laid low. He scornfully describes that arrogance which led the Jews to despise all threats and admonitions as long as they enjoyed prosperity, as is customary with all hypocrites. Therefore, he says that when their pride has been laid aside, they will afterwards be more submissive; not that they will change their dispositions, but because shame will restrain the wantonness in which they formerly indulged.

Therefore, we ought to supply an implied contrast here. He addresses those who were puffed up by ambition, carried their heads high, and despised everyone, as if they were not even subject to God. For they ventured to curse and insult God Himself and to mock His holy word. Isaiah says, This pride shall be laid low, and this arrogance shall cease.

And thy voice shall be out of the ground. What he previously said he expresses more fully by a metaphor: that they will utter a low and confused noise as out of caverns. The voice of those who were once so haughty and fierce is compared by him to the speech of soothsayers, who, in issuing their oracles from some deep and dark cave underground, uttered some sort of confused muttering; for they did not speak articulately, but whispered. He declares that these boasters (ἀλάζονες) will resemble them.

Some interpret this expression as if the Prophet meant that they will derive no benefit from the chastisement, but the words do not convey this meaning, and he says afterwards that the Jews will be brought to repentance. Yet he first strikes terror to repress their insolence, for they arrogantly and rebelliously scorned all the threats of the Prophet. Therefore, by their being “brought down,” he means nothing less than that they will be covered with disgrace, so that they will not dare to utter, as from a lofty place, their proud and idle boastings.