:
1 By the rivers of Babylon, there we sat down, yea, we wept, when we remembered Zion. 2 We hanged our harps upon the willows in the midst thereof. 3 For there they that carried us away captive required of us a song; and they that wasted us required of us mirth, saying, Sing us one of the songs of Zion. 4 How shall we sing the LORD's song in a strange land? 5 If I forget thee, O Jerusalem, let my right hand forget her cunning. 6 If I do not remember thee, let my tongue cleave to the roof of my mouth; if I prefer not Jerusalem above my chief joy. 7 Remember, O LORD, the children of Edom in the day of Jerusalem; who said, Rase it, rase it, even to the foundation thereof. 8 O daughter of Babylon, who art to be destroyed; happy shall he be, that rewardeth thee as thou hast served us. 9 Happy shall he be, that taketh and dasheth thy little ones against the stones.
[AD 311] Methodius of Olympus on Psalms 137:1-2
To continue with our subject, let us take in our hands and examine this psalm, which the pure and stainless souls sing to God, saying, “By the rivers of Babylon, there we sat down; we wept, when we remembered Zion. We hanged our harps on the willows in the midst thereof,” clearly giving the name of harps to their bodies, which they hung on the branches of chastity, fastening them to the wood that they might not be snatched away and dragged along again by the stream of incontinence. For Babylon, which is interpreted “disturbance” or “confusion,” signifies this life around which the water flows, while we sit in the midst of the water that flows round us, as long as we are in the world, the rivers of evil always beating on us. Wherefore, also, we are always fearful, and we groan and cry with weeping to God, that our harps may not be snatched off by the waves of pleasure and slip down from the tree of chastity.

[AD 430] Augustine of Hippo on Psalms 137:1
...But today we have sung, "By the waters of Babylon we sat down and wept, when we remembered Sion" [Psalm 137:1]....

[AD 430] Augustine of Hippo on Psalms 137:2
"On the willows in the midst thereof we hung up our instruments of music" [Psalm 137:2]. The citizens of Jerusalem have their "instruments of music," God's Scriptures, God's commands, God's promises, meditation on the life to come; but while they are dwelling "in Babylon," they "hang up their instruments." Willows are unfruitful trees, and here so placed, that no good whatever can be understood of them: elsewhere perhaps there may. Here understand barren trees, growing by the waters of Babylon. These trees are watered by the waters of Babylon, and bring forth no fruit; just as there are men greedy, covetous, barren in good works, citizens of Babylon in such wise, that they are even trees of that region; they are fed there by these pleasures of transitory things, as though watered by "the waters of Babylon." You seek fruit of them, and nowhere findest it....Therefore by deferring to apply the Scriptures to them, "we hang up our instruments of music upon the willows." For we hold them not worthy to carry our instruments. We do not therefore insert our instruments into them and bind them to them, but defer to use them, and so hang them up. For the willows are the unfruitful trees of Babylon, fed by temporal pleasures, as by the "waters of Babylon."

[AD 430] Augustine of Hippo on Psalms 137:3
"For there they that led us captive demanded of us words of songs, and they that led us away, an hymn" [Psalm 137:3]. They demanded of us words of songs and an hymn, who led us captive....We are tempted by the delights of earthly things, and we struggle daily with the suggestions of unlawful pleasures; scarce do we breathe freely even in prayer: we understand that we are captives. But who led us captive? What men? What race? What king? If we are redeemed, we once were captives. Who has redeemed us? Christ. From whom has He redeemed us? From the devil. The devil then and his angels led us captive: and they would not lead us, unless we consented....

[AD 390] Gregory of Nazianzus on Psalms 137:4
Certainly not, friends and brethren—I still call you “brethren,” though your attitude is not brotherly—do not let us accept such a view. We must not be like fiery, unruly horses, throwing reason our rider and spitting out the bit of discretion that so usefully restrains us, and running wide of the turning post. Let us conduct our debates within our frontiers and not be carried away to Egypt or dragged off to Assyria. Let us not “sing the song of the Lord in a foreign land,” by which I mean before any and every audience, heathen or Christian, friend or foe, sympathetic or hostile: these keep all too close a watch on us, and they would wish that the spark of our dissensions might become a conflagration; they kindle it, they fan it, by means of its own draught they raise it to the skies, and without our knowing what they are up to, they make it higher than the flames of Babylon that blazed all around. Having no strength in their own teaching, they hunt for it in our weakness, and for this reason like flies settling on wounds, they settle on our misfortune—or should I say our mistakes? Let us be blind to our doings no longer, and let us not neglect the proprieties in these matters. If we cannot resolve our disputes outright, let us at least make this mutual concession, to utter spiritual truths with the restraint due to them, to discuss holy things in a holy manner and not be broadcast to profane hearing what is not to be divulged.

[AD 430] Augustine of Hippo on Psalms 137:4
"Those" then "who have led us captive," the devil and his angels, when have they spoken unto us: "Sing us one of the songs of Sion"? What answer we? Babylon bears you, Babylon contains you, Babylon nourishes you, Babylon speaks by your mouth, you know not to take in save what glitters for the present, you know not how to meditate on things of eternity, you take not in what you ask. "How shall we sing the Lord's song in a strange land?" [Psalm 137:4]. Truly, brethren, so it is. Begin to wish to preach the truth in such measure as you know it, and see how needful it is for you to endure such mockers, persecutors of the truth, full of falsehood. Reply to them, when they ask of you what they cannot take in, and say in full confidence of your holy song, "How shall we sing the Lord's song in a strange land!"

[AD 430] Augustine of Hippo on Psalms 137:5
But take heed how you dwell among them, O people of God, O body of Christ, O high-born band of wanderers (for your home is not here, but elsewhere), lest when you love them, strivest for their friendship, and fearest to displease such men, Babylon begin to delight you and thou forget Jerusalem. In fear then of this, see what the Psalmist subjoins, see what follows. "If I forget you, O Jerusalem" [Psalm 137:5], amid the speeches of those who hold me captive, amid the speeches of treacherous men, amid the speeches of men who ask with ill intent, asking, yet unwilling to learn....What then? "If I forget you, O Jerusalem, let my right hand forget me."

[AD 430] Augustine of Hippo on Psalms 137:6
"Let my tongue cleave to my jaws, if I remember not you" [Psalm 137:6]. That is, let me be dumb, he says, if I remember not you. For what word, what sound does he utter, who utters not songs of Sion? That is our tongue, the song of Jerusalem. The song of the love of this world is a strange tongue, a barbarous tongue, which we have learned in our captivity. Dumb then will he be to God, who forgets Jerusalem. And it is not enough to remember: for her enemies too remember her, desiring to overthrow her. "What is that city?" say they; "who are the Christians? What sort of men are the Christians? Would they were not Christians." Now the captive band has conquered its capturers; still they murmur, and rage, and desire to slay the holy city that dwells as a stranger among them. Not enough then is it to remember: take heed how you remember. For some things we remember in hate, some in love. And so, when he had said, "If I forget you, O Jerusalem," etc., he added at once, "if I prefer not Jerusalem in the height of my joy." For there is the height of joy where we enjoy God, where we are safe of united brotherhood, and the union of citizenship. There no tempter shall assail us, no one be able so much as to urge us on to any allurement: there nought will delight us but good: there all want will die, there perfect bliss will dawn on us.

[AD 430] Augustine of Hippo on Psalms 137:7
Then he turns to God in prayer against the enemies of that city. "Remember, O Lord, the children of Edom" [Psalm 137:7]. Edom is the same who is also called Esau: for you heard just now the words of the Apostle read, "Jacob have I loved, but Esau have I hated." [Romans 9:13] ...Esau then signifies all the carnal, Jacob all the spiritual....All carnal persons are enemies to spiritual persons, for all such, desiring present things, persecute those whom they see to long for things eternal. Against these the Psalmist, looking back to Jerusalem, and beseeching God that he may be delivered from captivity, says— what? "Remember, O Lord, the children of Edom." Deliver us from carnal men, from those who imitate Esau, who are elder brethren, yet enemies. They were first-born, but the last-born have won the pre-eminence, for the lust of the flesh has cast down the former, the contempt of lust has lifted up the latter. The other live, and envy, and persecute. "In the day of Jerusalem." The day of Jerusalem, wherein it was tried, wherein it was held captive, or the day of Jerusalem's happiness, wherein it is freed, wherein it reaches its goal, wherein it is made partaker of eternity? "Remember," says he, "O Lord," forget not those "who said, Rase it, rase it, even to the foundation thereof." Remember then, it means, that day wherein they willed to overthrow Jerusalem. For how great persecutions has the Church suffered! How did the children of Edom, that is, carnal men, servants of the devil and his angels, who worshipped stocks and stones, and followed the lusts of the flesh, how did they say, "Extirpate the Christians, destroy the Christians, let not one remain, overthrow them even to the foundation!" Have not these things been said? And when they were said, the persecutors were rejected, the martyrs crowned....

[AD 253] Origen of Alexandria on Psalms 137:8-9
And in this way also the just give up to destruction all their enemies, which are their vices, so that they do not spare even the children, that is, the early beginnings and promptings of evil. In this sense also we understand the language of Psalm 137: “O daughter of Babylon, who is to be destroyed; happy shall he be that rewards you as you have served us; happy shall he be that takes and dashes your little ones against the stones.” For “the little ones” of Babylon (which signifies confusion) are those troublesome sinful thoughts that arise in the soul, and one who subdues them by striking, as it were, their heads against the firm and solid strength of reason and truth, is the person who “dashes the little ones against the stones”; and he is therefore truly blessed. God may therefore have commanded people to destroy all their vices utterly, even at their birth, without having enjoined anything contrary to the teaching of Christ. And he may himself have destroyed before the eyes of those who were “Jews inwardly” all the offspring of evil as his enemies. And, in like manner, those who disobey the law and word of God may well be compared with his enemies led astray by sin; and they may well be said to suffer the same fate as they deserve who have proved traitors to the truth of God.

[AD 397] Ambrose of Milan on Psalms 137:8-9
And David, pitying her, says, “O wretched daughter of Babylon.” Wretched indeed, as being the daughter of Babylon, when she ceased to be the daughter of Jerusalem. And yet he calls for a healer for her and says, “Blessed is he who shall take your little ones and dash them against the rock.” That is to say, shall dash all corrupt and filthy thoughts against Christ, who by his fear and his rebuke will break down all actions against reason, so as, if any one is seized by an adulterous love, to extinguish the fire, that he may by his zeal put away the love of a harlot and deny himself that he may gain Christ.

[AD 430] Augustine of Hippo on Psalms 137:8
Then he turns himself to her, "O daughter of Babylon, unhappy;" unhappy in your very exulting, your presumption, your enmity; "unhappy daughter of Babylon!" [Psalm 137:8]. The city is called both Babylon, and daughter of Babylon: just as they speak of "Jerusalem" and "the daughter of Jerusalem," "Sion" and "the daughter of Sion," "the Church" and "the daughter of the Church." As it succeeds the other, it is called "daughter;" as it is preferred before the other, it is called "mother." There was a former Babylon; did the people remain in it? Because it succeeds to Babylon, it is called daughter of Babylon. O daughter of Babylon, "unhappy" thou!...

[AD 430] Augustine of Hippo on Psalms 137:9
"Happy shall he be that repays you, as you have served us." What repayment means he? Herewith the Psalm closes, "Happy, that takes and dashes your little ones against the rock" [Psalm 137:9]. Her he calls unhappy, but him happy who pays her as she has served us. Do we ask, what reward? This is the repayment. For what has that Babylon done to us? We have already sung in another Psalm, "The words of the wicked have prevailed against us." For when we were born, the confusion of this world found us, and choked us while yet infants with the empty notions of various errors. The infant that is born destined to be a citizen of Jerusalem, and in God's predestination already a citizen, but meanwhile a prisoner for a time, when learns he to love ought, save what his parents have whispered into his ears? They teach him and train him in avarice, robbery, daily lying, the worship of various idols and devils, the unlawful remedies of enchantments and amulets. What shall one yet an infant do, a tender soul, observing what its elders do, save follow that which it sees them doing. Babylon then has persecuted us when little, but God has given us when grown up knowledge of ourselves, that we should not follow the errors of our parents....How shall they repay her? As she has served us. Let her little ones be choked in turn: yea let her little ones in turn be dashed, and die. What are the little ones of Babylon? Evil desires at their birth. For there are, who have to fight with inveterate lusts. When lust is born, before evil habit gives it strength against you, when lust is little, by no means let it gain the strength of evil habit; when it is little, dash it. But you fear, lest though dashed it die not; "Dash it against the Rock; and that Rock is Christ." [1 Corinthians 10:4]