Wow, this whole chapter is filled with admonition...and promise.
The Apostle Paul had visited Galatia prior to the writing of this book. He had preached the message of Jesus Christ to them and many received it...and received Christ.
In this chapter he is obviously pleading with them to turn back because he heard they had fallen away. He describes how they had become heirs to God when they accepted Christ. That through this acceptance, through faith in Him, they were adopted into the family of God. Before that they were under bondage with the world and basically in cahoots with Satan, the enemy often referred to in scripture.
Before I go on, this sounds much like the world today. So many have received Christ and live in freedom, knowing there is an eternal life that awaits them upon death. But there are many who have chosen, despite their knowledge of God, to live in the world. It's not just knowing who Christ is, it's knowing Him personally. Living in the world is bondage, according to Paul. In Christ we have freedom.
If a person serves the world, they serve the gods of the world, not the God of heaven. These Galatians turned back to the world, back to "the weak and beggarly elements, to which you desire again to be in bondage (Galatians 4:9b)."
Paul goes on to say that "they" (the world) are courting them and causing them to be turned away from the belief in Christ as Savior. He says in verse 19: "My little children, for whom I labor in birth again until Christ is formed in you..." He is, through his letter, attempting to help them turn back and stop listening and looking to the world. Look back to Christ whom they had accepted. Christ is the answer. It is important to keep our faith in Jesus Christ and not with man. Don't look to man for your salvation or the answers to life's questions. Man is not capable of granting either.
Paul later describes to them, perhaps reminding them, how Abraham had two sons, Ishmael the first and Isaac the second. Ishmael was born of Sarah, Abraham's wife's, maidservant (out of wedlock). Isaac was Sarah's son through her marriage with Abraham. God had given Abraham a promise that he would become the father of many nations (and Sarah the mother of many nations). Because Ishmael was out of wedlock, this promise, this covenant with God and Abraham, did not apply. Galatians 4:20 - But he who was of the bondwoman (maidservant) was born according to the flesh, and he of the freewoman (Sarah) through promise. It was a spiritual birth, through faith. Through Isaac came the continuance of the seed which brought Jesus, our promise, into this world.
If we hold tight to our belief in Christ, and let go of the world, we are also considered children of the freewoman. As long as we are in the world and serve in the world, we are children of the bondwoman, illegitimate. I personally was a child of the bondwoman for most of my life. We are all born in the flesh but have the opportunity to be adopted into the freewoman's family, becoming a child of God, because of the covenant God made with Abraham.
What I like about this story is the fact that even Abraham messed up! He jumped ahead (with the maidservant) of God's perfect timing instead of waiting for God to move in his life (with Sarah). Abraham messed up! We mess up too. But once we have accepted Christ, God forgives. We are now in Christ and no longer in the world. Until that time of acceptance, we flounder in the world. We are born in the flesh, not the Spirit. When we accept Christ, we are then born in the Spirit. In other words, we are born again in Christ.
The Promise is ours for the taking. We must be open to receive and willing to follow Christ. Our lives will be changed. Whatever we experience in life from that point on we have the Promise to look forward to. Jesus, our Promise. Jesus, our Life.
Galatians 4:30 - Nevertheless what does the Scripture say? ''Cast out the bondwoman and her son, for the son of the bondwoman shall not be heir with the son of the freewoman."