Thou hast broken down all his walls. The prophet, although he might easily have found another cause to which to impute the breaking down and razing of the fortifications, yet under the influence of devout and sanctified feeling acknowledges God to be the author of this calamity; being fully convinced that men could not at their pleasure have destroyed the kingdom which God had set up had not the Divine anger been kindled. Afterwards speaking metaphorically, he complains that the kingdom was exposed as a prey to all passers-by, resembling a field or garden, of which the walls were broken down, and the ground laid open to depredation. As an aggravation of a calamity which in itself was sufficiently grievous, the additional indignity is brought forward, that the king was a reproach to his neighbors. The worldly and the profane, there can be no doubt, finding an opportunity so much according to their wishes, derided him, saying, Is this that king of God's choice, a king more excellent than the angels, and whose throne was to continue as long as the sun and the moon should endure? As these railings recoiled upon God himself, the prophet justly complains of the reproachful derision with which God's Anointed was treated, whose dignity and royal estate were ratified and confirmed by heavenly anointing.

Thou hast broken down all his hedges - His walls or defenses; all that he relied on for safety.
Thou hast brought his strongholds to ruin - His towers, fortifications; defenses. The enemy has been suffered to destroy them. They are now heaps of ruins.

Thou hast broken down all his hedges - Thou hart permitted the land to be stripped of all defense; there is not even one strong place in the hands of thy people.

Thou hast broken down all his hedges,.... Round about his vine, the church; see Psalm 80:12. A famous church was raised at Jerusalem, quickly after the death, resurrection, and ascension of Christ, which seemed to be well filled, fenced, and protected; but on a sudden a violent persecution arose, and the members of it were made havoc of, and the ministers of the word were scattered abroad, and which was the breaking down of the hedges; and what was done to the church was taken by Christ as done to himself, as it is here spoken of him; see Acts 8:1, and this might seem contrary to the word and oath of God, that his seed should endure for ever, and his throne as the days of heaven, Psalm 89:29, when the first Christian church was used in this manner; but that providence was overruled, for the spread of the Gospel, and the interest of Christ, in other parts; see Acts 8:4, and so no objection to what is before said:
thou hast brought his strong holds to ruin; the same as before, the church of Christ, which seemed to be so well built and fortified; see Isaiah 26:1.

The ruin is depicted under several figures--a vineyard whose broken "hedges," and "strongholds," whose ruins invite spoilers and invaders; a warrior, whose enemies are aided by God, and whose sword's "edge"--literally, "rock" or "strength" (Joshua 5:2) is useless; and a youth prematurely old.