21. Surely God shall wound, etc. The enemies of the Church are fierce and formidable, and it is impossible that she can be preserved from their continued assaults, without a vigorous protection being extended. To persuade us that she enjoys such a defense, David represents God as armed with dreadful power for the overthrow of the ungodly. The verse stands connected as to scope with the preceding, and we might render the Hebrew particle אך, ach, by wherefore, or on which account; but it seems better to consider it as expressing simple affirmation. We are to notice the circumstance, that God counts all those his enemies who unjustly persecute the righteous, and thus assures us of his being always ready to interpose for our defense. The concern he feels in our preservation is forcibly conveyed by the expressions which follow, that he will wound the head of his enemies, and the crown of their hair; (43) intimating, that he will inflict a deadly and incurable wound upon such as harass his Church. This is still more strikingly brought out in what is added immediately afterwards, when God is described as wading through destruction.
(43) Bishops Hare and Horsley suppose that there is here an allusion to the usage of the people in those Arabian regions, who nourished their hair on the crown of their head, that by their unshorn heads and shaggy hair they might appear more fierce. “The expressions, ‘the head,’ and ‘the hairy crown,’” observes Bishop Horne, “denote the principal part, the strength, the pride, and the glory of the adversary which was to be crushed;” and Roberts, in his Oriental Illustrations, observes, that “this language, ‘ wounding the crown of the hair, ’ still used in the East, is equivalent to saying, ‘I will kill you.’”