6 “Turn again then unto your rest, O my soul; for the Lord has done good to you”: not for your deservings, or through your strength; but because the Lord has done good to you. “Since,” he says, “He has delivered my soul from death”. It is wonderful, most beloved brethren, that, after he had said that his soul should turn unto rest, since the Lord had rewarded him; he added, since “He has delivered my soul from death.” Did it turn unto rest, because it was delivered from death? Is not rest more usually said of death? What is the action of him whose life is rest, and death disquietude? Such then ought to be the action of the soul, as may tend to a quiet security, not one that may increase restless toil; since He has delivered it from death, who, pitying it, said, “Come unto Me, all you that labour and are heavy laden, and I will give you rest,” etc. Meek therefore and humble, following, so to speak, Christ as its path, should the action of the soul be that tends towards repose; nevertheless, not slothful and supine; that it may finish its course, as it is written, “In quietness make perfect your works.” “You have delivered my soul from death, my eyes from tears, and my feet from falling.” Whoever feels the chain of this flesh, chants these things as fulfilled in hope towards himself. For it is truly said, “I was in misery, and He delivered me;” but the Apostle says this also truly, that we are saved by hope. And that we are delivered from death, is well said to be already fulfilled, so that we may understand the death of unbelievers, of whom he says, “Leave the dead to bury their dead.”...He will then clear our eyes of tears, when He shall save our feet from falling. For there will then be no slipping of our feet as they walk, when there will be no sliding of the weak flesh. But now, however firm our path, which is Christ, be; yet since we place flesh, which we are enjoined to subdue, beneath us; in the very work of chastening and subduing it, it is a great thing not to fall: but not to slip in the flesh, who can attain? “I shall please in the sight of the Lord, in the land of the living”....We “labour” indeed now, because we are awaiting “the redemption of our body:” but, “when death shall have been swallowed up in victory, and this corruptible shall have put on incorruption, and this mortal immortality;” then there will be no weeping, because there will be no falling; and no falling, because no corruption. And therefore we shall then no longer labour to please, but we shall be entirely pleasing in the sight of the Lord, in the land of the living.
7....“I believed,” says he, “and therefore did I speak. But I was sorely brought down”. For he suffered many tribulations, for the sake of the word which he faithfully held, faithfully preached; and he was sorely brought down; as they feared who loved the praise of men better than that of God. But what means, “But I”? He should rather say, I believed, and therefore I have spoken, and I was sorely brought down: why did he add, “But I,” save because a man may be sorely brought down by those who oppose the truth, the truth itself cannot, which he believes and speaks? Whence also the Apostle, when he was speaking of his chain, says, “the word of God is not bound.” So this man also, since there is one person of the holy witnesses, that is, of the Martyrs of God, says, “I believed, and therefore will I speak.” “But I;” not that which I believed, not the word which I have delivered; “but I was sorely brought down.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)