That grace has not failed yet, and it will never fail, because it comes from the inexhaustible supply of the infinite and eternally merciful and gracious God. We are eternally blessed if we know, worship and serve him.
Two things are said of those who will be brought to the worship of God in the days the psalmist envisions.
1. The people will acknowledge God. The word "acknowledge” in verse 4 is a translation of the Hebrew verb yadah, which has a rich variety of meanings. It can mean "know,” “acknowledge,” “understand," “be sure," "know about," "experience” and other variations. In the New International Version it is translated no less than 190 different ways to get as close as possible to the meaning. Here it means more than merely admitting that there is such a God as Jehovah or even acknowledging him as the one true God. It means coming to him in a saving relationship, bowing before him, and seeking to know him better. It means exactly what Jesus meant when he said in the great prayer recorded in John 17, "This is eternal life: that they may know you, the only true God, and Jesus Christ, whom you have sent" (v. 3).
The theme of these verses is Gentiles and Jews in Jesus' fold. Even more, it is the chief idea of the psalm. The idea is that in the latter days envisioned by the psalmist the Gentile nations will join the sons and daughters of Israel in acknowledging and worshipping the true God. I also call it the chief idea because it is from this that the psalmist gets his vision of a true brotherhood of nations and world peace.
There are any number of ways to partition this psalm, short as it is. The New International Version divides it into two stanzas (vv. 1-4 and vv. 5-7). But the psalm's themes unfold almost verse by verse, and I think it best merely to take the ideas in sequence. The first occurs in verses 1 and 2, which are the theme verses of the psalm. Their point is that God has chosen and established Zion. Therefore, by inference, Zion cannot be shaken even though the entire world should unite in arms against it. It is this that caused Newton to write
On the Rock of Ages founded,
What can shake thy sure repose?
Yet sometimes the Jews rose to greater heights of vision and saw the goal of peace as something God himself would achieve and by means very different from those of godless nations. Psalm 87 embraces such a vision. It is a prophecy that anticipates a day when the heathen nations of Egypt, Babylon, Philistia, Tyre and Cush, and no doubt many others since these are clearly representative, will be received as citizens of Zion, the poetical name for God's rule over God's people from Jerusalem.
