Those who trust in the Lord are like Mount Zion, which cannot be moved, but abides forever. As the mountains surround Jerusalem, so the Lord surrounds his people, from this time forth and forevermore. —Psalm 125:1-2
Calvin on the meaning of this psalm,
Although the world is subject to so many and so sudden changes as almost to put on a new face every moment, and although the faithful are mingled with and placed in the same external condition as others, yet their safety continues steadfast under the invincible protection of God. (Commentary on the Book of Psalms, vol. V, p. 90.)
Calvin is right. You could stop reading now and be good to go. But there is more here. If we were to flip through the surrounding pages we see that the superscript in Psalm 125 is repeated. In fact, Psalms 120–134 are all "Songs of Ascents." This refers to Israel’s "coming up" out of Babylonian captivity and sets the theme as Israel’s return from exile to Jerusalem. Each psalm shows us a little more.
Song of Ascents Rundown
Psalm 120 gives the exilic cry, "Woe is me, that I sojourn in Meschech, that I dwell among the tents of Kedar!" (v. 5). Then Psalm 121 reminds us that the Lord is our keeper, he’ll keep our going out and coming in (v. 8). Psalm 122 directs us to a restored Jerusalem as our hope and prayer (v. 5). This is to say, a Jerusalem under the kingship of Messiah (v. 6).
Then Psalm 123 refines our hope—"our eyes look to the Lord our God." (v. 2). The Lord alone is our salvation. And Psalm 124 assures us of this by recounting Israel’s deliverance from Egypt (vv. 1-5).
Psalm 125 interjects a vision of Jerusalem once more. Mount Zion (Jerusalem) is the picture of one who trusts in the Lord. This person, like Jerusalem, will not be moved but abides forever. Psalm 126 longs for this reality, "Restore our fortunes, O Lord!" (v. 4). Psalm 127 then configures our hope to the blessing of children. But it’s not just any children. This "Song of Ascents of Solomon" looks to the offspring of David. David’s son, Solomon, is still looking for the promised son. Psalm 128 envisions the flourishing of Jerusalem under the reign of David’s son. Psalm 129 is another snapshot of reality. Circumstances are bad for this exiled people, but the Lord is righteous and all who hate Zion will be put to shame (v. 5).
Psalm 130 and 131 model what it means to have faith, calling for Israel to hope in the Lord (130:7; 131:3). Then Psalm 132 comes with the central message of the Songs of Ascents: The Lord made a promise to David to set one of his sons on the throne of Zion forever. This is one of the clearest pictures of Old Testament faith in Jesus. It’s followed in Psalm 133 with a picture of unity, a glorious implication of a reunited kingdom. And then Psalm 134 concludes that ordering our worship, "bless the Lord!"
So What About Psalm 125?
Calvin is right, remember? The circumstances of this world are volatile and crazy, but God’s people live under his invincible protection. But why? How? This is what the surrounding Songs of Ascents help us understand. Our hope in an abiding, protected, eternal Jerusalem is a hope in Messiah and his reign. God’s promise to David about Jesus included a dwelling place of peace—no disturbance, no violence (2 Samuel 7:10-11). But you don’t get a Jerusalem like that without a king like Jesus. That’s what Psalm 125 is getting at.
Mount Zion cannot be shaken because another mountain was. Actually, it was a hill, called Golgotha. Years after this psalm was written, one Friday afternoon, at about the ninth hour, this promised King died. Jesus Christ died for us, bearing the wrath we deserved. He suffered in our place, making atonement for our sins. The only reason the Lord can "surround his people from this time forth and forevermore" is because on that hill he didn’t surround his Son.
But this King would live forever. Yes, and after his thorns and cross came his throne and crown. Jesus conquered our sin in his death. Then he conquered death by his resurrection. And it’s because of this—and this alone—that we can go about our days under the Lord‘s invincible protection. The tomb is empty, Jesus reigns, and we cannot be moved.