John Calvin Commentary Isaiah 56:9

"All ye beasts of the field, come to devour, [yea], all ye beasts in the forest." — Isaiah 56:9 (ASV)

All you beasts of the field. This prediction appears to contradict what came before; for what the Prophet has until now said was full of the most delightful consolation, but now he appears to threaten fiercely and to predict frightful ruin.

These statements might indeed appear to be contradictory. However, after having comforted believers, it should not be considered inconsistent if he forewarns them of a future calamity so that they might not lose courage when they see everything near destruction, and that necessity might also prompt them to turn more warmly and earnestly to the grace of God.

There is also another reason: hypocrites abuse the promises of God, claim them under false pretenses, cherish unfounded hope, and insolently boast of those things that do not belong to them at all. Therefore, Isaiah intended to remove from them the basis for false boasting.

And thus his design was twofold:

1. that the hearts of believers might not be discouraged by various calamities, which would bring them almost to utter destruction, and that even when, amidst prosperity and peace, they saw by faith at a distance a future calamity, they might rest satisfied with this single consolation;
2. that he might strike hypocrites with dread and horror, so that they might not exalt themselves with vain confidence or freely indulge their sinful inclinations under the pretense of these promises.

For this reason, God calls them not men, but savage “beasts,” so that they might devour the people. He therefore forbids believers to be alarmed and tempted to unbelief when these wild beasts will be sent. And yet, he also intended to strike terror into them, to arouse them to repentance, and to exhort them to seek the mercy of God, so that the promises might not lose their value.

When he calls them “beasts of the field,” he means beasts of every kind, and includes not only the Babylonians and Assyrians, but Antiochus, the Romans, and other enemies of the people, who brought various calamities upon them. But he primarily has in view the defeat that they received from the Babylonians, who carried them away into wretched bondage.