Daleth
25 “My soul cleaves to the pavement: O quicken Thou me according to Your word”. What means, “My soul cleaves to the pavement, O quicken Thou me according to Your word”?...If we look upon the whole world as one great house, we see that the heavens represent its vaulting, the earth therefore will be its pavement. He wishes therefore to be rescued from earthly things, and to say with the Apostle, “Our conversation is in heaven.” To cling therefore to earthly things is the soul's death; the contrary of which evil, life is prayed for, when he says, “O quicken Thou me.”
26....The body itself also, because it is of the earth, is reasonably understood by the word pavement; since, because it is still corruptible and weighs down the soul, we justly groan while in it, and say unto God, “O quicken Thou me.” For we shall not be without our bodies when we shall be for evermore with the Lord; but then because they will not be corruptible, nor will they weigh down our souls, if we view it strictly, we shall not cleave unto them, but they rather unto us, and we unto God....
27. For what he was by himself, he confesses in the following words: “I have acknowledged my ways, and You heard me”. Some copies indeed read, “Your ways:” but more, and the best Greek, read “my ways,” that is, evil ways. For he seems to me to say this; I have confessed my sins, and You have heard me; that is, so that You would remit them. “O teach me Your statutes.” I have acknowledged my ways: You have blotted them out: teach me Yours. So teach me, that I may act; not merely that I may know how I ought to act. For as it is said of the Lord, that He knew not sin, and it is understood, that He did no sin; so also he ought truly to be said to know righteousness, who does it. This is the prayer of one who is improving....
28. Finally he adds, “Intimate to me the way of Your righteousness”; or, as some copies have it, “instruct me;” which is expressed more closely from the Greek, “Make me to understand the way of Your righteousnesses; so shall I be exercised in Your wondrous things.” These higher commandments, which he desires to understand by edification, he calls the wondrous things of God. There are then some righteousnesses of God so wondrous, that human weakness may be believed incapable of fulfilling them by those who have not tried. Whence the Psalmist, struggling and wearied with the difficulty of obeying them, says, “My soul has slumbered for very heaviness: O establish Thou me with Your word!”. What means, has slumbered? save that he has cooled in the hope which he had entertained of being able to reach them. But, he adds, “Stablish Thou me with Your word:” that I may not by slumbering fall away from those duties which I feel that I have already attained: establish Thou me therefore in those words of Yours that I already hold, that I may be able to reach unto others through edification.
29. “Take Thou from me the way of iniquity”. And since the law of works has entered in, that sin might abound; he adds, “And pity me according to Your law.” By what law, save by the law of faith? Hear the Apostle: “Where is boasting then? It is excluded. By what law? Of works. Nay: but by the law of faith.” This is the law of faith, whereby we believe and pray that it may be granted us through grace; that we may effect that which we cannot fulfil through ourselves; that we may not, ignorant of God's righteousness, and going about to establish our own, fail to submit ourselves unto the righteousness of God.
30. But after he had said, “And pity me according to Your law;” he mentions some of those blessings which he has already obtained, that he may ask others that he has not yet gained. For he says, “I have chosen the way of truth: and Your judgments I have not forgotten”. “I have stuck unto Your testimonies: O Lord, confound me not”: may I persevere in striving toward the point whereunto I am running: may I arrive whither I am running! So then “it is not of him that wills, nor of him that runs, but of God that shows mercy.” He next says, “I will run the way of Your commandments, when You have widened my heart”. I could not run had Thou not widened my heart. The sense of the words, “I have chosen the way of truth, and Your judgments I have not forgotten: I have stuck unto Your testimonies,” is clearly explained in this verse. For this running is along the way of the commandments of God. And because he does allege unto the Lord rather His blessings than his own deservings; as if it were said unto him, How have you run that way, by choosing, and by not forgetting the judgments of God, and by sticking to His testimonies? Couldest thou do these things by yourself? I could not, he replies. It is not therefore through my own will, as though it needed no aid of Yours; but because “You have widened my heart.” The widening of the heart is the delight we take in righteousness. This is the gift of God, the effect of which is, that we are not straitened in His commandments through the fear of punishment, but widened through love, and the delight we have in righteousness....
Source: The Enarrations, or Expositions, on the Psalms (New Advent)