In Gal 4, Paul continues his defense of justification by faith, not works or obedience to the law. He gives an illustration of how young children are in the same position as slaves even if they are heirs to great wealth. They have to obey their guardians until they reach adulthood. Paul says it's the same way with us before Christ came. "But when the right time came, God sent his Son... to buy freedom for us who were slaves the the law, so that He could adopt us as His very own children... and everything He has belongs to you." Paul asks the Galatians, then, "why do you want to go back again and become slaves once more? ... trying to find favor with God by what you do or don't do ?" Paul says once more, "we are not obligated to the law, but are acceptable to God because of our faith". Life can be discouraging and even depressing if we dwell on thoughts of guilt or inadequacy because of our inability to perform perfect obedience to God. Rejoice in God's grace and know that our status before God depends only on our faith in Christ's greatness, not our ability to live up to the expectations or demands of the law or other people.