1 They that trust in the LORD shall be as mount Zion, which cannot be removed, but abideth for ever. 2 As the mountains are round about Jerusalem, so the LORD is round about his people from henceforth even for ever. 3 For the rod of the wicked shall not rest upon the lot of the righteous; lest the righteous put forth their hands unto iniquity. 4 Do good, O LORD, unto those that be good, and to them that are upright in their hearts. 5 As for such as turn aside unto their crooked ways, the LORD shall lead them forth with the workers of iniquity: but peace shall be upon Israel.
[AD 373] Athanasius of Alexandria on Psalms 125:1
For to those who thus examine themselves and conform their hearts to the Lord, nothing adverse shall happen; for indeed, their hearts are strengthened by confidence in the Lord, as it is written, “They who trust in the Lord are as Mount Zion; he who dwells in Jerusalem shall not be moved forever.” For if at any time, the crafty one shall be presumptuously bold against them, chiefly that he may break the rank of the saints and cause a division among brethren; even in this the Lord is with them, not only as an avenger on their behalf but also when they have already been beaten, as a deliverer for them.

[AD 407] John Chrysostom on Psalms 125:1
Such, however, is not the nature of the righteous person. But what manner of person is he? Hear the same prophet, saying, “They that trust in the Lord are as Mount Zion.” What does the phrase “as Mount Zion” mean? “He shall not be shaken forever,” he says. For whatever engines [instruments of warfare] you bring up, whatever darts you hurl, desiring to overturn a mountain, you will never be able to prevail. For how can you? You will break in pieces all your engines and exhaust your own strength. Such also is the righteous person. Whatever blows he may receive, he suffers no evil therefrom but destroys the power of those who take counsel against him, and not of human beings only but of demons. You have heard often what engines the devil brought up against Job. But not only did he fail to overthrow that mountain but drew back exhausted, his darts broken to pieces and his engines rendered useless, by that assault!

[AD 430] Augustine of Hippo on Psalms 125:1
"They that put their trust in the Lord shall be even as the mount Sion: they shall not be removed for ever" [Psalm 125:1].

[AD 430] Augustine of Hippo on Psalms 125:2
What is this Jerusalem? He briefly describes it. "The mountains stand around Jerusalem" [Psalm 125:2]. Is it anything great, that we are in a city surrounded by mountains? Is this the whole of our happiness, that we shall have a city which mountains surround? Do we not know what mountains are? Or what are mountains save swellings of the earth? Different then from these are those mountains that we love, lofty mountains, preachers of truth, whether Angels, or Apostles, or Prophets. They stand around Jerusalem; they surround her, and, as it were, form a wall for her. Of these lovely and delightful mountains Scripture constantly speaks....They are the mountains of whom we sing: "I lifted up my eyes unto the mountains, from whence my help shall come:" because in this life we have help from the holy Scriptures. And through the mountains that receive peace, the little hills received righteousness: for what says he of the mountains themselves? He said not, they have peace from themselves, or they make peace, or generate peace; but, they receive peace. The Lord is the source, whence they receive peace. So therefore lift up your eyes to the mountains for the sake of peace, that your help may come from the Lord, who has made heaven and earth. Again, the Holy Spirit mentioning these mountains says this: "Thou dost light them wonderfully from Your everlasting mountains." He said not, the mountains light them: but, Thou lightest them from Your everlasting mountains: through those mountains whom You have willed to be everlasting, preaching the Gospel, Thou lighting them, not the mountains. Such then are the "mountains that stand around Jerusalem."

[AD 430] Augustine of Hippo on Psalms 125:3
"For the Lord will not leave the rod of the ungodly upon the lot of the righteous, lest the righteous put forth their hands unto wickedness" [Psalm 125:3]. At present indeed the righteous suffer in some measure, and at present the unrighteous sometimes tyrannize over the righteous. In what ways? Sometimes the unrighteous arrive at worldly honours: when they have arrived at them, and have been made either judges or kings; for God does this for the discipline of His folk, for the discipline of His people; the honour due to their power must needs be shown them. For thus has God ordained His Church, that every power ordained in the world may have honour, and sometimes from those who are better than those in power. For the sake of illustration I take one instance; hence calculate the grades of all powers. The primary and every day relation of authority between man and man is that between master and slave. Almost all houses have a power of this sort. There are masters, there are also slaves; these are different names, but men and men are equal names. And what says the Apostle, teaching that slaves are subject to their masters? "Servants, be obedient to them that are your masters according to the flesh:" for there is a Master according to the Spirit. He is the true and everlasting Master; but those temporal masters are for a time only. When you walk in the way, when you live in this life, Christ does not wish to make you proud. It has been your lot to become a Christian, and to have a man for your master: you were not made a Christian, that you might disdain to be a servant. For when by Christ's command you serve a man, you serve not the man, but Him who commanded you. He says this also: "Servants, be obedient to them that are your masters according to the flesh." [Ephesians 6:5] Behold, he has not made men free from being servants, but good servants from bad servants. How much do the rich owe to Christ, who orders their house for them! so that if you have had an unbelieving servant, suppose Christ convert him, and say not to him, Leave your master, you have now known Him who is your true Master: he perhaps is ungodly and unjust, you are now faithful and righteous: it is unworthy that a righteous and faithful man should serve an unjust and unbelieving master. He spoke not thus unto him, but rather, Serve him: and to confirm the servant, added, Serve as I served; I before you served the unjust....If the Lord of heaven and earth, through whom all things were created, served the unworthy, asked mercy for His furious persecutors, and, as it were, showed Himself as their Physician at His Advent (for physicians also, better both in art and health, serve the sick): how much more ought not a man to disdain, with his whole mind, and his whole good will, with his whole love to serve even a bad master! Behold, a better serves an inferior, but for a season. Understand what I have said of the master and slave, to be true also of powers and kings, of all the exalted stations of this world. For sometimes they are good powers, and fear God; sometimes they fear not God. Julian was an infidel Emperor, an apostate, a wicked man, an idolater; Christian soldiers served an infidel Emperor; when they came to the cause of Christ, they acknowledged Him only who was in heaven. If he called upon them at any time to worship idols, to offer incense; they preferred God to him: but whenever he commanded them to deploy into line, to march against this or that nation, they at once obeyed. They distinguished their everlasting from their temporal master; and yet they were, for the sake of their everlasting Master, submissive to their temporal master.

[AD 379] Basil of Caesarea on Psalms 125:4-5
God is good, but he is also just, and it is the nature of the just to reward in proportion to merit, as it is written: “Do good, O Lord, to those that are good and to the upright of heart. But such as turn aside to their own crooked ways, the Lord shall lead out with the workers of iniquity.” He is merciful, but he is also a judge, for “the Lord loves mercy and judgment,” says the psalmist. And he therefore also says, “Mercy and judgment I will sing to you, O Lord.” We have been taught who they are on whom he has mercy: “Blessed are the merciful,” says the Lord, “for they shall obtain mercy.” You see with what discernment he bestows mercy, neither being merciful without judgment nor judging without mercy, for “the Lord is merciful and just.” Let us not, therefore, know God by halves or make his loving-kindness an excuse for our indolence; for this, his thunders, for this, his lightnings—that his goodness may not be held in dispute. He who causes the sun to rise also strikes people with blindness. He who sends the rain also causes the rain of fire. By the one he manifests his goodness; by the other, his severity. For the one let us love him, for the other let us fear, that it may not be said also to us, “Or do you despise the riches of his goodness and patience and longsuffering? Do you not know that the kindness of God leads you to penance? But according to your hardness and impenitent heart, you store up for yourself wrath against the day of wrath.”

[AD 430] Augustine of Hippo on Psalms 125:4
And he therefore adds, "Do well, O Lord, unto those that are good and true of heart" [Psalm 125:4]. They who are right in heart, of whom I was speaking a little before—they who follow the will of God, not their own will,— reflect upon this. But they who wish to follow God, allow Him to go before, and themselves to follow; not themselves to go before, and Him to follow; and in all things they find Him good, whether chastening, or consoling, or exercising, or crowning, or cleansing, or enlightening; as the Apostle says, "We know that all things work together for good to them that love God." [Romans 8:28]

[AD 430] Augustine of Hippo on Psalms 125:4-5
Therefore, the devil and his angels, by turning from the light and warmth of charity and going over to pride and envy, were made numb as by an icy hardness. Therefore they are figuratively located in the north. Thus, while the devil weighed down the human race, the future grace of the Savior was spoken of in the Canticle of Canticles thus: “Arise, O north wind, and come, O south wind, blow through my garden and let the aromatical spices thereof flow.” Arise, you who did rush in, who does weigh on the conquered, who does oppress those whom you own, arise, that those whose souls you have pressed on and bowed down may be relieved of your weight and may lift up their heads. “And come, O south wind,” he says, calling on the spirit of grace, breathing from the south, as from a warm and luminous quarter, “that the aromatical spices may flow.” Hence the apostle says, “We are the good odor of Christ in every place.” Hence, also, it says in another psalm, “Turn again our captivity, O Lord, as a stream in the south”; doubtless, the captivity in which they were held under the devil, as under the north wind, where they were chilled by abounding iniquity, and were, so to speak, frozen. Hence, also, the Gospel says, “And because iniquity has abounded, the charity of many shall grow cold.” But, truly, when the south wind blows, the ice is melted and the streams flow; that is, when their sins are forgiven the people flock to Christ by charity. Hence, also, it is written elsewhere, “And your sins are melted away as the ice in the fair, warm weather.”

[AD 430] Augustine of Hippo on Psalms 125:5
Whence the Psalmist at once adds: "As for such as turn aside, the Lord shall lead them forth unto strangling with the workers of unrighteousness" [Psalm 125:5]: that is, those whose deeds they have imitated; because they took delight in their present pleasures, and did not believe in their punishments to come. What then shall they have, who are righteous in heart, and who turn not back? Let us now come to the heritage itself, brethren, for we are sons. What shall we possess? What is our heritage? What is our country: what is it called? Peace. In this we salute you, this we announce to you, this the mountains receive, and the little hills receive as righteousness. Peace is Christ: "for He is our peace, who has made both one, and has broken down the middle wall of partition between us." [Ephesians 2:14] Since we are sons, we shall have an inheritance. And what shall this inheritance be called, but peace? And consider that they who love not peace are disinherited. Now they who divide unity, love not peace. Peace is the possession of the pious, the possession of heirs. And who are heirs? Sons....Since then Christ the Son of God is peace, He therefore came to gather together His own, and to separate them from the wicked. From what wicked men? From those who hate Jerusalem, who hate peace, who wish to tear unity asunder, who believe not peace, who preach a false peace to the people, and have it not. To whom answer is made, when they say, "Peace be with you," "And with your spirit:" but they speak falsely, and they hear falsely. Unto whom do they say, Peace be with you? To those whom they separate from the peace of the whole earth. And unto whom is it said, "And with your spirit"? To those who embrace dissensions, and who hate peace. For if peace were in their spirit, would they not love unity, and leave dissensions? Speaking then false words, they hear false words. Let us speak true words, and hear true words. Let us be Israel, and let us embrace peace; for Jerusalem is a vision of peace, and we are Israel, "and peace is upon Israel."