Galatians 4:27. “For it is written, Rejoice, thou barren that bearest not; break forth and cry, thou that travailest not; for the desolate hath many more children than she which hath an husband.”
This passage is a direct quote from Isaiah 54:1. It may seem strange to insert it here, but consider the context.
The previous chapter in Isaiah is chapter 53, where we have the fullest, most complete prophecy of the coming into the world of the Lord Jesus, His suffereing and death and resurrection, that is to be found anywhere in the Bible. Isaiah seems to see Christ on His cross: “He was wounded for our transgressions, He was bruised for our iniquities: the chastisement of our peace was upon Him; and with His stripes we are healed. All we like sheep have gone astray; we have turned, every one, to his own way; the the Lord hath laid on Him the iniquity of us all” (Is. 53:5,6).. The final verse in Isaiah 53 says, “He bare the sin of many, and made intercession for the transgressors.”
And then, the very next word is “Sing!” We are to rejoice in the matchless grace that God showed us in Jesus Christ. Rejoice because Jesus has died, the sin question is settled, and now God can let free grace flow unhindered to us poor sinners.
Grace, before Jesus, had been like a woman who was forsaken and alone, and longed to be the mother of children, but wept and mourned alone.
On the other hand, legalism is typified by another woman who has thousands of children, people who profess to be saved by their own effort. Legalism seems to be a fruitful, rejoicing mother, while grace is left to mourn.
But then Grace is set free, the Gospel goes out to the world, and the one who mourned becomes the mother of many more children than legalism has.
Heaven will be populated by the children of Grace, not the children of legalism. And there will be millions and millions who have partaken of the wonderful grace of Jesus!