The conclusion of the entire Hagar-Sarah allegory emphasizes once again the identification of believers in Christ: Therefore, brothers, we are not children of the slave woman, but of the free woman. The freedom-slavery and Spirit-flesh antitheses which Paul has constructed in his allegory serve as the framework for his ethical instructions in the rest of the letter. The children of the free woman, who were born by the power of the Spirit (v. 29) must learn to express their freedom by walking in the Spirit. They must not submit to slavery under the law or gratify the desires of the flesh.

Identity is the basis of behavior: a clear understanding of who we are in Christ guides our conduct in the Spirit.