Chapter 4 of Galatians delves deeper into the transformative journey from bondage under the law to the glorious freedom of sonship in Christ. Paul uses the analogy of a child under a guardian to illustrate the restrictive nature of the law and contrasts it with the freedom attained through faith in Christ. The pivotal moment is marked by God sending His Son to redeem those under the law and to adopt them as sons, granting the Spirit of His Son into believers' hearts. Paul introduces the allegory of Sarah and Hagar, representing the two covenants: one of the promise and freedom and the other of bondage and the law. He expresses his perplexity and concern over the Galatians turning back to the weak and miserable principles of the law and pleads for them to remain in the freedom of the Gospel of grace.

In chapter 5, Paul explicitly addresses the essence of Christian freedom, warning against the circumventing influence of the law and advocating for steadfastness in the liberty of Christ. He condemns the act of circumcision as a means to gain righteousness, emphasizing that those who adhere to the law are obliged to obey it entirely and are estranged from Christ. He propounds love as the fulfilling of the law and cautions against using liberty as an occasion for the flesh. The chapter delineates the conflict between the flesh and the Spirit, listing the works of the flesh and contrasting them with the fruit of the Spirit. Believers are exhorted to walk in the Spirit, thereby not gratifying the desires of the flesh, and to serve one another in love.