6 But love such mountains, in whom the Lord is. Then do those very mountains love you, if you have not placed hope in them. See, brethren, what the mountains of God are. Thence they are so called in another passage: “Your righteousness is like the mountains of God.” Not their righteousness, but “Your righteousness.” Hear that great mountain the Apostle. “That I may be found in Him, not having my own righteousness, which is of the law, but that which is through the faith of Christ.” But they who have chosen to be mountains through their own righteousness, as certain Jews or Pharisees their rulers, are thus blamed: “Being ignorant of God's righteousness, and going about to establish their own righteousness, they have not submitted themselves unto the righteousness of God.” But they who have submitted themselves are exalted in such a manner as to be humble. In that they are great, they are mountains; in that they submit themselves unto God, they are valleys: and in that they have the capacity of piety, they receive the plenteousness of peace, and transmit the copious irrigation to the hills, only beware, at present, what mountains you love. If you wish to be loved by good mountains, place not your trust even in good mountains. For how great a mountain was Paul? Where is one like him found? We speak of the greatness of men. Can any one readily be found of so great grace? Nevertheless, he feared lest that bird should place trust in him: and what does he say: “Was Paul crucified for you?” But lift up your eyes unto the mountains, whence help may come unto you: for, “I have planted, Apollos has watered:” but, your help comes from the Lord, who has made Heaven and earth; for, “God gave the increase.” “The mountains,” therefore, “stand around Jerusalem.” But as “the mountains stand around Jerusalem, even so stands the Lord round about His people, from this time forth for evermore.” If therefore the mountains stand around Jerusalem, and the Lord stands round about His people, the Lord binds His people into one bond of love and peace, so that they who trust in the Lord, like the mount Sion, may not be moved for evermore: and this is, “from this time forth for evermore.”
7. “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”. 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.” 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.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)