3 He adds, how He became our refuge, since He began to be that, viz. a refuge, to us which He had not been before, not that He had not existed before He became our refuge: “Before the mountains were brought forth, or ever the earth and the world were made: and from age even unto age You are”. Thou therefore who art for ever, and before we were, and before the world was, hast become our refuge ever since we turned to You. But the expression, “before the mountains,” etc., seems to me to contain a particular meaning; for mountains are the higher parts of the earth, and if God was before even the earth were formed (or, as some books have it, from the same Greek word, “framed”), since it was by Him that it was formed, what is the need of saying that He was before the mountains, or any certain parts of it, since God was not only before the earth, but before heaven and earth, and even the whole bodily and spiritual creation?
But it may certainly be that the whole rational creation is marked by this distinction; that while the loftiness of Angels is signified by the mountains, the lowliness of man is meant by the earth. And for this reason, although all the works of creation are not improperly said to be either made or formed; nevertheless, if there is any propriety in these words, the Angels are “made;” for as they are enumerated among His heavenly works, the enumeration itself is thus concluded: “He spoke the word, and they were made; He commanded, and they were created;” but the earth was “formed,” that man might thence be created in the body.
For the Scripture uses this word, where we read, God made, or “God formed man out of the dust of the ground.” Before then the noblest parts of the creation (for what is higher than the rational part of the Heavenly creation) were made: before the earth was made, that You might have worshippers upon the earth; and even this is little, as all these had a beginning either in or with time; but “from age to age You are.” It would have been better, from everlasting to everlasting: for God, who is before the ages, exists not from a certain age, nor to a certain age, which has an end, since He is without end.
But it often happens in the Scripture, that the equivocal Greek word causes the Latin translator to put age for eternity and eternity for age. But he very rightly does not say, You were from ages, and unto ages You shall be: but puts the verb in the present, intimating that the substance of God is altogether immutable. It is not, He was, and Shall be, but only Is. Whence the expression, I Am that I Am; and, I Am “has sent me unto you;” and, “You shall change them, and they shall be changed: but You are the same, and Your years shall not fail.” Behold then the eternity that is our refuge, that we may fly there from the mutability of time, there to remain for evermore.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)