1 How long wilt thou forget me, O LORD? for ever? how long wilt thou hide thy face from me? 2 How long shall I take counsel in my soul, having sorrow in my heart daily? how long shall mine enemy be exalted over me? 3 Consider and hear me, O LORD my God: lighten mine eyes, lest I sleep the sleep of death; 4 Lest mine enemy say, I have prevailed against him; and those that trouble me rejoice when I am moved. 5 But I have trusted in thy mercy; my heart shall rejoice in thy salvation. 6 I will sing unto the LORD, because he hath dealt bountifully with me.
[AD 390] Diodorus of Tarsus on Psalms 13:1
The psalm’s theme, in fact, is clear: it is uttered on the part of David himself when he suffered the effects of the sin with Bathsheba. On falling foul of every harsh, grievous and painful incident on that account, remember, he then identified the sin as the cause, especially on hearing that “the Lord has taken away your sin.” You see, while he received the gift as coming from a loving Lord, he thought it behooved him not to forget the sin but instead to advance in virtue with the degree of determination he required to be preserved from committing such a sin against so good a lord. But on being caught up in the events involving Absalom in particular, he believed the outcome was God’s abandoning him and realized the sin was most of all to blame. He therefore asks God to be completely reconciled to him and not forsake him but to lift the weight of misfortune that was proving too heavy for the strength of the sufferer.

[AD 407] John Chrysostom on Psalms 13:1
Whence comes his knowledge that God had forgotten him, does the text say? Since he knew also when he remembered him, and he was wise enough to know what forgetting meant and what remembering. Not like the majority of people, who, when they are wealthy, when they enjoy a good reputation with people, when everything goes favorably for them, when they better their foes, then think God remembers them. Hence neither do they understand when it is God forgets them. They do not recognize the sign of God’s remembering, you see, nor do they grasp the sign of his forgetting.… Nothing, after all, brings remembrance by God so much as doing good, being sober and watchful, practicing virtue; likewise, nothing prompts forgetting so much as living in sin and giving oneself to greed and rapacity. So for your part, dearly beloved, when you are in trouble, do not say, “God has forgotten me,” but when you are living in sin and everything is going favorably for you. After all, if you knew this, you would quickly abandon evil things.

[AD 430] Augustine of Hippo on Psalms 13:1
"For Christ is the end of the law to every one that believes." [Romans 10:4] "How long, O Lord, will You forget me unto the end?" [Psalm 13:1] that is, put me off as to spiritually understanding Christ, who is the Wisdom of God, and the true end of all the aim of the soul. "How long will You turn away Your face from me?" As God does not forget, so neither does He turn His face away: but Scripture speaks after our manner. Now God is said to turn away His face, when He does not give to the soul, which as yet has not the pure eye of the mind, the knowledge of Himself.

[AD 450] Hesychius of Jerusalem on Psalms 13:1
The forgetfulness of God [would be] a very serious thing, even temporarily. It would mean death, the loss of immortality.

[AD 585] Cassiodorus on Psalms 13:1
He asks for the appearance of Christ whom he already foresaw. For his face is what was capable of being seen with the eyes of the body, which that holy man with this general longing rightly desired to look upon. Such a face deemed it right to save the world by his heavenly appearance.

[AD 253] Origen of Alexandria on Psalms 13:2
At first this one makes many plans in his soul, but in the end [see v. 5], he rests in the great plan of God for everyone, whose spirit is in the root of Jesse.

[AD 407] John Chrysostom on Psalms 13:2
Just as the sailor on leaving port wanders in every direction and the person deprived of light bumps into many things, so too the one who encounters God’s forgetting is caught up constantly in worries and cares and sorrows.

[AD 430] Augustine of Hippo on Psalms 13:2
"How long shall I place counsel in my soul?" [Psalm 13:2]. There is no need of counsel but in adversity. Therefore "How long shall I place counsel in my soul?" is as if it were said, How long shall I be in adversity? Or at least it is an answer, so that the meaning is this, So long, O Lord, will You forget me to the end, and so long turn away Your face from me, until I shall place counsel in my own soul: so that except a man place counsel in his own soul to work mercy perfectly, God will not direct him to the end, nor give him that full knowledge of Himself, which is "face to face." "Sorrow in my heart through the day?" How long shall I have, is understood. And "through the day" signifies continuance, so that day is taken for time: from which as each one longs to be free, he has sorrow in his heart, making entreaty to rise to things eternal, and not endure man's day.

[AD 253] Origen of Alexandria on Psalms 13:3
Is God a light to enlighten the eyes of the body or the eyes of the intellect? The prophet says of the latter, “Enlighten my eyes lest I sleep in death.” I think it is clear to everyone that we would not say that God performs the work of the sun and assigns to another the task of enlightening the eyes of those who will not sleep in death. God, therefore, enlightens the mind of those whom he judges to be worthy of personal enlightenment. But if God illuminates the mind according to the statement “The Lord is my light,” then we must assume that he is apprehended by the intellect and is invisible and incorporeal, because he is the light of the mind.

[AD 339] Eusebius of Caesarea on Psalms 13:3
The face of God, full of light, is a certain power looking to confer gifts, by which each partaker will be enlightened, as if they were enjoying the rays of the sun. But if one has turned away, his spirit lives in the shadows without light; because the eyes within, namely, the thoughts of the mind, can see nothing. When one persists in sin, more and more shadows come, because deep within him the face of God remains turned away.

[AD 390] Gregory of Nazianzus on Psalms 13:3
If you are blind and unenlightened, lighten your eyes that you sleep not in death. In God’s Light see light, and in the Spirit of God be enlightened by the Son, that threefold and undivided Light.

[AD 390] Diodorus of Tarsus on Psalms 13:3
Since the misfortunes and the tribulations render the sun, which is a source of pleasure to everyone, dim and faint to me, he is saying, free me from the misfortune so that I may see good things as they naturally are and not as the tribulations represent them.

[AD 407] John Chrysostom on Psalms 13:3
Just as when God defends us and stands by us, everything damaging is removed from us, so when he keeps his distance and forgets us, our soul is cut in two, our heart plunged in sorrow, those who do harm fall on us and life becomes craggy and precipitous. Now, this is allowed to happen for our advantage, so that through the whole of it those more indifferent people may be goaded into becoming more zealous and return to the condition from which they fell. “Your falling away will instruct you, after all,” Scripture says, “and your wickedness censure you.” And so even abandonment by God is a form of providence. You see, when the one who exercises providence and care is slighted, he ignores and abandons us to some extent so that at that point indifference may be expelled and the negligent may turn more zealous.

[AD 430] Augustine of Hippo on Psalms 13:3
"Look on me, and hear me, O Lord my God" [Psalm 13:3]. "Look on me," refers to what was said, "How long" dost "Thou turn away Your face from me." "Hear," refers to what was said, "How long will You forget me to the end? Lighten my eyes, that I sleep not in death." The eyes of the heart must be understood, that they be not closed by the pleasurable eclipse of sin.

[AD 444] Cyril of Alexandria on Psalms 13:3
The right sight of the eyes hidden within is to be able to see plainly and subtly, insofar as is allowed, whatever considerations there may be concerning the words of God. “For we see through a mirror in an obscure manner and we know in part,” but “he who discloses the recesses of the darkness” sends the light of truth to those who wish to gain a knowledge concerning him rightly. It is necessary therefore that we prostrate ourselves before God saying, “Give light to my eyes that I may not sleep in death,” for to slip away from the rightness of holy doctrines would be nothing else except to sleep in death, and we depart from this rightness when we do not follow the divinely inspired Scriptures.

[AD 458] Theodoret of Cyrus on Psalms 13:3
By night I am overwhelmed by my problems, in the grip of discouragement like a kind of sleep. But if the light of your assistance shines, it will disperse the darkness of trouble and put an end to the sleep of discouragement. If, however, you delay your help, I am afraid the sleep will turn into death, as the distress becomes stronger than my resolve.

[AD 585] Cassiodorus on Psalms 13:3
The eyes of the heart … sleep in death when they are closed by the pleasure of the flesh and the light of faith is buried. This is the sort of sleep in which the enemy rejoices.

[AD 339] Eusebius of Caesarea on Psalms 13:4
As we sin, the adversary becomes haughty and domineering over us, and we are pressed down by our sin; this is really the nature of sin, to cast down and to oppress the spirit.

[AD 407] John Chrysostom on Psalms 13:4
What is the meaning of “I have prevailed over him”? That even if he is not absolutely strong, yet he has proved strong against me. Our defeat clothes him in strength, makes him look strong, powerful and invincible. Do you see that when we sin, not only do we shame and destroy ourselves and fall headlong into death, but also we declare to be strong and powerful the foes by whom we are defeated. And not only this: we also bring them to a state of joy and exultation. Bless me! What stupidity! What madness! To be of assistance ourselves to our enemies and make their soul rejoice and exult through the pain and distress they cause us! See how absurd it is. Whereas we should conquer the enemy (“His swords have finally failed,” remember, “and the godless has been destroyed”), whereas we should conquer, we are beaten; and not only this, but we make him appear powerful and strong. Nor does the extent of our madness and extreme derangement stop at this point: We prove the cause of bringing him to a state of joy and exultation. Sin in reality is the height of madness and extreme evil.… Let us … give thought and expend effort lest we puff the enemy up, lest we show him to be strong, lest we give him joy; instead, let us do the opposite, make him humble, lowly, weak, dejected, gloomy. You see, if he were to see sinners reforming, all these things would happen together.

[AD 430] Augustine of Hippo on Psalms 13:4
"Lest at any time mine enemy say, I have prevailed against him" [Psalm 13:4]. The devil's mockery is to be feared. "They that trouble me will exult, if I be moved;" the devil and his angels; who exulted not over that righteous man, Job, when they troubled him; because he was not moved, that is, did not draw back from the steadfastness of his faith. [Job 2:3]

[AD 585] Cassiodorus on Psalms 13:4
If someone withdraws himself by a single mental step from the Lord’s strength, then he inevitably steps into the devil’s trap.

[AD 407] John Chrysostom on Psalms 13:5
Do you see a hope-filled soul? He asked, and before receiving he gives thanks as though having received, sings praise to God and achieves all that had been anticipated.

[AD 430] Augustine of Hippo on Psalms 13:5-6
"But I have hoped in Your mercy" [Psalm 13:5]. Because this very thing, that a man be not moved, and that he abide fixed in the Lord, he should not attribute to self: lest when he glories that he has not been moved, he be moved by this very pride. "My heart shall exult in Your salvation;" in Christ, in the Wisdom of God. "I will sing to the Lord who has given me good things;" spiritual good things, not belonging to man's day. "And I will chant to the name of the Lord most high" [Psalm 13:6]; that is, I give thanks with joy, and in most due order employ my body, which is the song of the spiritual soul. But if any distinction is to be marked here, "I will sing" with the heart, "I will chant" with my works; "to the Lord," that which He alone sees, but "to the name of the Lord," that which is known among men, which is serviceable not for Him, but for us.

[AD 458] Theodoret of Cyrus on Psalms 13:5
It is clear also from this that he uttered this psalm after the sin: he relies not on his righteousness but on mercy and says it is in this that he trusts.

[AD 585] Cassiodorus on Psalms 13:5
The love of God is a spring shower of virtues under which a blessed desire begins to bud and holy action bears fruit. This love is patient under adversities in this life, temperate in prosperity, powerful in its humility, joyful in affliction, benevolent toward enemies, and overcomes the wicked by its goodness. From this source, even heavenly creatures are constantly ignited by God’s love as a restoring flame, a growing desire for salvation. To summarize all of this with a phrase from the Apostle: “God himself is love.”

[AD 9999] Pseudo-Athanasius on Psalms 13:5
In this I trust, that I shall receive forgiveness of my sin, in that I hope in your mercy through which you have worked salvation for all people.

[AD 407] John Chrysostom on Psalms 13:6
Hope in God’s mercy, have no doubts, and you will gain your request completely; once gained, however, do not prove ungrateful for the favor and unappreciative but make a record of the kindness and offer it as a thanksgiving song to the Lord.