A son of the slave, or a son of the free?
“Tell me, you who want to be under the law, do you not understand the law? For it is written that Abraham had two sons, one by the slave woman and the other by the free woman. But one, the son by the slave woman, was born by natural descent, while the other, the son by the free woman, was born through the promise.” (Galatians 4:21 – 23, NET).
Paul compares the case of two sons to the two covenants; the Old and the New. He proceeds to show that those who insist on adding the works of the law to the justification by the faithfulness of Jesus are not free, they are slaves. Slaves could not inherit the property, and they do not represent the Master. The apostate Judaism, Paul declares, is in slavery to the law. Therefore, they are the children by human descent, by the flesh; and not children of the promise, in Jesus Christ. Jews were slaves to the Torah, including the ten commandments, because they promised to obey all that is commanded but failed to do so. Because they promised to do all they were told to do, the Jews made themselves, voluntarily, the bond-slaves to the law. Jesus confirms this, “‘So you too, when you have done everything you were commanded to do, should say, ‘We are slaves undeserving of special praise; we have only done what was our duty.”” (Luke 17:10, NET).
Paul compares the Old Covenant to Hagar and Ishmael. Hagar was a bond-slave; therefore, Ishmael was a slave also. Ishmael was by human descent, human effort bore him, and consequently, he could not be the son of the promise, and, therefore, was not eligible to inherit the property. Children of the slave have the “old nature” inherited from the first Adam. The “old nature,” old mind, is the slave to the law because it is trying to, by its efforts, look good and thus obligate God to grant them the eternal life. Those who are righteous by the faithfulness of Jesus Christ, however, are the new creation, the children of the promise, and therefore, the children of the free. They have a new nature, the holy nature, and the holy life of Jesus Christ. The new nature does the righteous works, because it is the right thing to do, not because they need it for their salvation. Anyone could do the “good works,” but only those who are saved by grace could do the righteous works.