2 There is then in this Psalm the voice of men troubled, and so indeed of Martyrs amid sufferings in peril, but relying on their own Head. Let us hear them, and speak with them out of sympathy of heart, though it be not with similarity of suffering. For they are already crowned, we are still in peril: not that such sort of persecutions do vex us as have vexed them, but worse perchance in the midsts of all kinds of so great scandals. For our own times do more abound in that woe, which the Lord cried: “Woe to the world because of scandals.” And, “Because iniquity has abounded, the love of man shall wax cold.” For not even that holy Lot at Sodom suffered corporal persecution from any one, or had it been told him that he should not dwell there: the persecution of him were the evil doings of the Sodomites. Now then that Christ sits in Heaven, now that He is glorified, now that necks of kings are made subject to His yoke, and their brows placed beneath His sign, now that not any one remains to dare openly to trample upon Christians, still, however, we groan amid instruments and singers, still those enemies of the Martyrs, because with words and steel they have no power, with their own wantonness do persecute them. And O that we were sorrowing for Heathens alone: it would be some sort of comfort, to wait for those that not yet have been signed with the Cross of Christ; when they should be signed, and when, by His authority attached, they should cease to be mad. We see besides men wearing on their brow the sign of Him, at the same time on that same brow wearing the shamelessness of wantonness, and on the days and celebrations of the Martyrs not exulting but insulting. And amid these things we groan, and this is our persecution, if there is in us the love which says, “Who is weak, and I am not weak? Who is scandalized, and I burn not?” Not any servant of God, then, is without persecution: and that is a true saying which the Apostle says, “But even all men that will to live godly in Christ, shall suffer persecution.”...
3. “O God, to my aid make speed”. For need we have for an everlasting aid in this world. But when have we not? Now however being in tribulation, let us especially say, “O God, to my aid make speed.” “Let them be confounded and fear that seek my soul.” Christ is speaking: whether Head speak or whether Body speak; He is speaking that has said, “Why do you persecute Me?” He is speaking that has said, “Inasmuch as you have done it to one of the least of Mine, to Me you have done it.” The voice then of this Man is known to be of the whole man, of Head and of Body: that need not often be mentioned, because it is known. “Be they confounded,” he says, “and fear that seek my soul.” In another Psalm He says, “I was looking unto the right and saw, and there was not one that would know Me: flight has perished from Me, and there is not one to seek out My soul.” There of persecutors He says, that there was not one to seek out His soul: but here, “Let them be confounded and fear that seek My soul.”...And where is that which you have heard from your Lord, “Love ye your enemies, do good to them that hate you, and pray for them that persecute you”? Behold you suffer persecution, and cursest them from whom you suffer, how do you imitate the Passions of your Lord that have gone before, hanging on the cross and saying, “Father, forgive them, for they know not what they do.” To persons saying such things the Martyr replies and says, you have set before me the Lord, saying, “Father, forgive them, for they know not what they do:” understand thou my voice also, in order that it may be yours too: for what have I said concerning mine enemies? “Let them be confounded and fear.” Already such vengeance has been taken on the enemies of the Martyrs. That Saul that persecuted Stephen, he was confounded and feared. He was breathing out slaughters, he was seeking some to drag and slay: a voice having been heard from above, “Saul, Saul, why do you persecute Me,” he was confounded and laid low, and he was raised up to obedience, that had been inflamed unto persecuting. This then the Martyrs desire for their enemies, “Let them be confounded and fear.” For so long as they are not confounded and fear, they must needs defend their actions: glorious they think themselves, because they hold, because they bind, because they scourge, because they kill, because they dance, because they insult, and because of all these doings they be some time confounded and fear. For if they be confounded, they will also be converted: because converted they cannot be, unless they shall have been confounded and shall have feared. Let us then wish these things to our enemies, let us wish them without fear. Behold I have said, and let me have said it with you, may all that still dance and sing and insult the Martyrs “be confounded and fear:” at last within these walls confounded may they beat their breasts!
Source: The Enarrations, or Expositions, on the Psalms (New Advent)