5 If haply any one asks, what person is speaking in this Psalm? I would say briefly, “It is Christ.” But as you know, brethren, and as we must say frequently, Christ sometimes speaks in His own Person, in the Person of our Head. For He Himself is “the Saviour of the Body.” He is our Head; the Son of God, who was born of the Virgin, suffered for us, “rose again for our justification,” sits “at the right hand of God,” to “make intercession for us:” who is also to recompense to the evil and to the good, in the judgment, all the evil and the good that they have done. He deigned to be come our Head; to become “the Head of the Body,” by taking of us that flesh in which He should die for us; that flesh which He also raised up again for our sakes, that in that flesh He might place before us an instance of the resurrection; that we might learn to hope for that of which we heretofore despaired, and might henceforth have our feet upon the rock, and might walk in Christ. He then sometimes speaks in the name of our Head; sometimes also He speaks of us who are His members. For both when He said, “I was an hungred, and you gave Me meat,” He spoke on behalf of His members, not of Himself: and when He said, “Saul, Saul, why do you persecute Me?” the Head was crying on behalf of its members: and yet He did not say, “Why do you persecute My members?” but, “Why do you persecute Me?” If He suffers in us, then shall we also be crowned in Him. Such is the love of Christ. What is there can be compared to this? This is the thing on account of which “He has put a hymn in our mouth,” and this He speaks on behalf of His members.
6. “The just shall see, and shall fear, and shall trust in the Lord.” “The just shall see.” Who are the just? The faithful; because it is “by faith that the just shall live.” For there is in the Church this order, some go before, others follow; and those who go before make themselves “an example” to those who follow; and those who follow imitate those who go before. But do those then follow no one, who exhibit themselves as an ensample to them that come after? If they follow no one at all, they will fall into error. These persons then must themselves also follow some one, that is, Christ Himself....“The just,” therefore, “shall see, and shall fear.” They see a narrow way on the one hand; on the other side, “a broad road:” on this side they see few, on the other many. But you are a just man; count them not, but weigh them; bring “a just balance,” not a “deceitful” one: because you are called just. “The just shall see, and fear,” applies to you. Count not therefore the multitudes of men that are filling the “broad ways,” that are to fill the circus tomorrow; celebrating with shouts the City's Anniversary, while they defile the City itself by evil living. Look not at them; they are many in number; and who can count them? But there are a few travelling along the narrow road. Bring forth the balance, I say. Weigh them; see what a quantity of chaff you lift up on the one side, against a few grains of grain on the other. Let this be done by “the just,” the “believers,” who are to follow. And what shall they who precede do? Let them not be proud, let them not “exalt themselves;” let them not deceive those who follow them. How may they deceive those who follow them? By promising them salvation in themselves. What then ought those who follow to do? “The just shall see, and fear: and shall trust in the Lord;” not in those who go before them. But indeed they fix their eyes on those who go before them, and follow and imitate them; but they do so, because they consider from Whom they have received the grace to go before them; and because they trust in Him. Although therefore they make these their models, they place their trust in Him from whom the others have received the grace whereby they are such as they are. “The just shall see it, and fear, and shall trust in the Lord.” Just as in another Psalm, “I lift up my eyes unto the hills,” we understand by hills, all distinguished and great spiritual persons in the Church; great in solidity, not by swollen inflation. By these it is that all Scripture has been dispensed unto us; they are the Prophets, they are the Evangelists; they are sound Doctors: to these “I lift up my eyes, from whence shall come my help.” And lest you should think of mere human help, he goes on to say, “My help comes from the Lord, which made heaven and earth. The just shall see it, and fear, and shall trust in the Lord.”...
7. “Blessed is that man that makes the name of the Lord his trust, and has not respected vanities or lying madnesses”. Behold the way by which you would fain have gone. Behold the “multitude that fill the Broad way.” It is not without reason “that” road leads to the amphitheatre. It is not without reason it leads to Death. The “broad way” leads unto death, its breadth delights for time: its end is straitness to all eternity. Aye; but the multitudes murmur; the multitudes are rejoicing together; the multitudes are hastening along; the multitudes are flocking together! Do not thou imitate them; do not turn aside after them: they are “vanities, and lying madnesses.” Let the Lord your God be your hope. Hope for nothing else from the Lord your God; but let the Lord your God Himself be your hope. For many persons hope to obtain from God's hands riches, and many perishable and transitory honours; and, in short, anything else they hope to obtain at God's hands, except only God Himself. But do thou seek after your God Himself: nay, indeed, despising all things else, make your way unto Him! Forget other things, remember Him. Leave other things behind, and “press forward” unto Him. Surely it is He Himself, who set you right, when turned away from the right path; who, now that you are set in the right path, guides you aright, who guides you to your destination. Let Him then be your hope, who both guides you, and guides you to your destination. Whither does worldly covetousness lead you? And to what point does it conduct you at the last? Thou at first desired a farm; then you would possess an estate; you would shut out your neighbours; having shut them out, you set your heart on the possessions of other neighbours; and extended your covetous desires till you had reached the shore: arriving at the shore, thou covet the islands: having made the earth your own, you would haply seize upon heaven. Leave thou all your loves. He who made heaven and earth is more beautiful than all.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)