John Calvin Commentary Isaiah 36:13

"Then Rabshakeh stood, and cried with a loud voice in the Jews` language, and said, Hear ye the words of the great king, the king of Assyria." — Isaiah 36:13 (ASV)

Therefore Rabshakeh stood, and cried with a loud voice in the Jewish language. The Prophet shows by what means Rabshakeh attempted to shake the heart of the people, and first relates that he spoke in the Jewish language, though the ambassadors urged him not to do so. It was, indeed, exceedingly shocking that the holy language, which had been consecrated to the mysteries of heavenly wisdom, was profaned and prostituted to wicked blasphemies; and this must undoubtedly have been a severe temptation to weak minds.

But this should lead us to remark that no enemies are more destructive than those who speak the same language as ourselves. Today we find this to be true in many who learn our language—that is, our way of speaking—so that they may be able to insinuate themselves into the ears of weak and ignorant persons, to draw them aside from the true faith.

Thirty years ago, the Papists had a language that was barbarous and totally at variance with the style of the Holy Spirit; they were scarcely heard to utter a word that breathed of Christian piety. But now they have succeeded in acquiring such skill that they know how to cloak their impieties under the ordinary language of Scripture, as if they were speaking in a Christian manner. Thus we see that it was Satan who devised that style, for he is their teacher and instructor as truly as he previously was the teacher and instructor of Rabshakeh.

When the Prophet says that he stood, he expresses the fierceness and insolence of the wicked man, for the very posture shows how haughtily he behaved. Previously he stood, but now he positioned himself to be better seen and to strike greater terror into the Jews.

Hear the words of the great king. Having already spoken of the greatness of his king, he repeats his commands. It is Satan’s custom to exaggerate in words the power of enemies and to represent dangers as greater than they really are, in order to compel us to lose courage; for when our eyes are dazzled by the vain splendor of earthly objects, we lose heart.

Therefore, we ought to contrast the power of God with all dangers. If we constantly keep that power before our eyes, nothing can harm us. With high disdain and great insolence, the enemies will boast of their greatness and strength and, on the other hand, will mock our feebleness and our small numbers; but if the Lord is with us, we have nothing to fear.