Psalms 87:5

5And it shall be said of Zion, Man and man is born in her. It is asserted, in the 4th verse, That new citizens shall be gathered into the Church of God from different parts of the world; and here the same subject is prosecuted. Another figure is however employed, which is, that strangers by birth shall be accounted among the holy people, just as if they were descended from Abraham. It had been stated in the preceding verse, that the Chaldeans and Egyptians would be added to the household of the Church; and that the Ethiopians, Philistines, and Tyrians, would be enrolled among her children. Now, it is added, by way of confirmation, that the number of the new progeny shall be exceeding great, so that the city which had been for a time uninhabited, and afterwards only half filled with a few people, shall be crowded with a vast population. The prophet Isaiah describes more at length what is here promised, in a few words,

“Sing, O barren, thou that didst not bear; break forth into singing, and cry aloud, thou that didst not travail with child: for more are the children of the desolate than the children of the married wife, saith the Lord. Enlarge the place of thy tent, and let them stretch forth the curtains of thine habitations: spare not, lengthen thy cords, and strengthen thy stakes: for thou shalt break forth on the right hand and on the left; and thy seed shall inherit the Gentiles, and make the desolate cities to be inhabited.” (Isaiah 54:1)

Also,

“Lift up thine eyes round about, and see; all they gather themselves together, they come to thee: thy sons shall come from far, and thy daughters shall be nursed at thy side.”
(Isaiah 60:4)

And, in the 44th chapter, at the 5th verse, we meet with almost the same language as in the passage before us, or at least what comes very near to it: “One shall say, I am the Lord’s; and another shall call himself by the name of Jacob; and another shall subscribe with his hand unto the Lord, and surname himself by the name of Israel.” Nor is the word born inappropriately employed to express the fact, that the Egyptians, Chaldeans, and such like, shall be of the flock of God’s people. Although Zion was not the place of their natural birth, but they were to be grafted into the body of the holy people by adoption; yet as the way by which we enter into the Church is a second birth, this form of expression is used with great propriety. The condition upon which Christ espouses the faithful to himself is, that they should forget their own people and their father’s house, (Psalms 45:11,) and that, being formed into new creatures, and born again of incorruptible seed, they should begin to be the children of God as well as of the Church, (Galatians 4:19.) And the ministry of the Church, and it alone, is undoubtedly the means by which we are born again to a heavenly life. By the way, we should remember the difference which the Apostle sets forth as subsisting between the earthly Jerusalem, — which, being herself a bondwoman, brings forth children also in bondage, — and the heavenly Jerusalem, which brings forth free children by the instrumentality of the Gospel.

In the second part of the verse, there is expressed the stability and enduring character of Zion. It often happens, that in proportion to the rapidity with which cities rise to distinguished eminence, is the shortness of the continuance of their prosperity. That it may not be thought that the prosperity of the Church is of such a perishable and transitory nature, it is declared, that the Most High himself will establish her It is not surprising, as if it had been said, to find other cities shaken, and subject from time to time to a variety of vicissitudes; for they are carried round with the world in its revolutions, and do not enjoy everlasting defenders. But it is the very reverse with respect to the new Jerusalem, which, being founded upon the power of God, will continue even when heaven and earth shall fall into ruins.