John Calvin Commentary Psalms 81:14

"I would soon subdue their enemies, And turn my hand against their adversaries." — Psalms 81:14 (ASV)

I would soon have brought their enemies low. Here the Israelites are taught that all the calamities which had befallen them were to be imputed to their own sins; for their enemies did not fight against them with any strength other than what was supplied to them from above.

God had promised that under His leadership the chosen people would prove victorious over all their enemies; and now, to remove any basis for accusing Him of breaking His word, He affirms that He would not have failed to enable them to do this, had He not been prevented by their sins.

He doubtless intends tacitly to remind them that the victories they had formerly achieved were not due to their own military valor, but to Him under whose guidance they had been placed. Now, He tells them that He was not only prevented by their sins from using His power to defend them, but He was also compelled by their perverseness to rush against them with the sword in His hand, while He left their enemies to remain in undisturbed tranquillity.