John Calvin Commentary Isaiah 34:8

"For Jehovah hath a day of vengeance, a year of recompense for the cause of Zion." — Isaiah 34:8 (ASV)

For it is the day of vengeance of Jehovah. This verse must be viewed as closely connected with the preceding verses, as it points out the purpose the Lord has in punishing the Edomites with such severity—namely, His desire to avenge His people and defend their cause. If, therefore, He had not also provided this reason, the former statements might have seemed obscure or inappropriate; indeed, our understanding would be uncertain if we did not consider that God, in punishing wicked men, testifies to His unceasing affection and care to preserve His own people.

What was previously said about the Edomites must undoubtedly be extended to all enemies of the Church, for the Prophet included all of them under this particular category.

Therefore, in adversity, our hearts should be supported by this consolation: the attacks we now endure will come into judgment before God, who justly claims this office for Himself.

The Prophet means not only that it is in God’s power to punish wicked men whenever He sees fit, but also that He reigns in heaven to punish every kind of injustice at the proper time.

But we must pay attention to the words day and year, by which the Prophet reminds us that God does not sleep in heaven.

Though for a short time He may not seem to intervene, He delays His vengeance until the right time, so that believers may in the meantime “possess their souls in patience” (Luke 21:19), and may leave Him to govern according to His inscrutable wisdom.