John Calvin Commentary Isaiah 3:9

"The show of their countenance doth witness against them; and they declare their sin as Sodom, they hide it not. Woe unto their soul! for they have done evil unto themselves." — Isaiah 3:9 (ASV)

The proof of their countenance will answer in them, or, will answer against them. Since the Prophet was dealing with impudent and brazen-faced hypocrites who arrogantly boasted that they were good people, he says that their countenance testifies what kind of individuals they are. Indeed, he states that it will not be necessary to bring witnesses from a distance to prove their wickedness, because to answer (in this context) means “to bear testimony,” or “to confess.” Therefore, although they disguise their face and countenance, so that they frequently deceive others, God still compels them to reveal what they are. Thus, in spite of themselves, they carry, as it were, a mark of their deceit and hypocrisy on their forehead.

Some explain it by saying that their crimes are so manifest that they cannot avoid seeing, as in a mirror, the baseness which they desire to conceal. But the former meaning is confirmed by what immediately follows: that they declared their sin in the same manner as the inhabitants of Sodom. By these words, he intimates that they devoted themselves to iniquity in such a way that they boasted of their transgressions without any shame, as if it had been honorable and praiseworthy in them to trample on every distinction between right and wrong, and also to indulge in every kind of wickedness. On this account, he compares them to the inhabitants of Sodom (Genesis 18:20, 19:5), who were so much blinded by their lusts that they rushed, with brutish stupidity, to everything base. So, then, this is the answer of the countenance, which he mentioned earlier: that they carry about with them plain tokens of impiety, which are abundantly sufficient to prove their guilt.

Woe unto their soul! Here he declares what was previously mentioned: that the whole cause of their calamities is to be found in themselves. For by their sins and iniquities they provoked the Lord. Consequently, they have no means of evasion, and it is useless to devise empty excuses, because the evil itself dwells in their bones. It is as if he had said, “God cannot be accused, as if He punished you unjustly. Acknowledge that you have brought this upon yourselves; give glory to a righteous judge and lay the whole blame on yourselves.”