Galatians 4:21-31 The difference between believers who rested in Christ only, and those who trusted in the law, is explained by the lives of Isaac and Ishmael. These things are an example and the Spirit of God points out something further. Hagar and Sarah are examples of the new and old covenant. The heavenly Jerusalem, the true church from above, represented by Sarah, is in a state of freedom, and is the mother of all believers, who are born of the Holy Spirit.  They were by regeneration and true faith, made a part of the true seed of Abraham, according to the promise made to him.  Hagar is of the earth, always fighting for survival receiving their reward while on earth and never taking it into eternal life. A life of torment – never being good enough. So then, we are not children of the bond-woman, but of the free. We would not have found out this example in the history of Sarah and Hagar, if it had not been shown to us, and this is what was intended by the Holy Spirit