John Calvin Commentary Isaiah 33:23

"Thy tacklings are loosed; they could not strengthen the foot of their mast, they could not spread the sail: then was the prey of a great spoil divided; the lame took the prey." — Isaiah 33:23 (ASV)

Thy cords were loosed. He directs his discourse to the Assyrians, and through them, he also addresses all the enemies of the Church. After promising the Church stability that will never be disturbed, he rebukes the foolish confidence with which ungodly men are puffed up; as if they were so deeply rooted as to reach the center of the earth. Although, during the intoxicating influence of prosperity, they imagine that their wealth is exceedingly secure, he foretells that ruin will quickly overtake them because they are not supported by the hand of God.

He continues the comparison he used at the beginning. Having said that the Church resembles a fortified place, surrounded by very broad rivers that prevent the approach of enemies, he now compares the condition of wicked men to ships. By this, he means that they have no solid foundation, even though they appear formidable, are madly eager and fiercely cruel, and imagine that no one can resist their rage.

Therefore, although they have long ships and cargo ships, by which they might be said to connect countries far apart and make themselves masters of sea and land, they will still have no permanence or stability. The Lord will sink their ships, take away their ropes and masts, and involve them in a universal shipwreck. Therefore, let us not be terrified by their fury and insolence, but let us look for the day of the Lord, when He will make their rage and violence fall on their own heads.