Read Isaiah 54:1.

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 (Isaiah 54:1).

Sarah, the type of the heavenly Jerusalem, was barren. Hagar, the type of those who attempt to gain the Divine inheritance by the works of the Law, was able to bring forth a son immediately. But the children of Sarah will be infinitely greater in number than the children of Hagar because the children of Sarah include Christ and all who are part of Christ.

This is a principle of the Kingdom of God. Those who attempt to work for God may bring forth a large work of some kind. Those who wait on the Lord may be barren of results for many years. But in the end, those who wait on the Lord will have an inconceivably greater fruitfulness than those who attempt to build the Kingdom of God by seeking to use the promises of the Scriptures in their own wisdom and strength.

The mother of Samuel, the mother of Samson, the mother of John the Baptist, are other examples of barren women who gave birth according to the promise of God.

When we think about the difference in the fruit brought forth by Sarah, by Hannah, by Elizabeth, and the fruit brought forth by Hagar, we begin to understand the enormous difference in results between waiting on God, and going forth to accomplish things in our own way.

Those who would attempt to build the Kingdom of God by their own wisdom and strength are able to bring visible results quickly. It appears that they have succeeded, and what they have produced will mock and vaunt itself against the "small things" of the saint who is waiting patiently for the Lord to fulfil His promises, to build His Church, His Kingdom, in His own time and manner (Genesis 21:9; Zechariah 4:10.)

When the Lord God of Heaven begins to work according to His promises, the results are much greater than anything the flesh could accomplish. The Glory of the Lord is revealed for all to see. The Lord alone is exalted and the flesh is cast down.

In the case of the "barren," the "woman forsaken and grieved in spirit," of the fifty-fourth chapter of Isaiah, her "children" are the holy city, the new Jerusalem, the Tabernacle of God, the Lamb’s Wife (Isaiah 54:11-17; Revelation 21:2,39).