Paul used another illustration to relate that during the time the Jews were bound by the old law, they were like children being raised by guardians until they became of age. They had no more legal rights during that period of instruction than did a household slave.
Jesus came to relieve that bondage and as one accepts that gift through faithful obedience, he becomes a son, then an heir of God through Christ. The Galatians had allowed themselves to be persuaded by the Judaizing teachers to leave their freedom in Christ and to turn to the slavery of the Jewish law.
Paul had rejected the bondage of the law and had accepted the freedom in Christ. He wanted the Galatians to likewise turn from their errors and to become like him in their obedience.
The Galatians had welcomed Paul as a messenger of God when he had first come to them. In reminding them of this fact, he urged them to not look upon him as an enemy because of the truth of his teaching.
As the Judaizing teachers led the Galatians astray, they were very zealous in their work. Zeal for the right thing is good but Paul said that they should remain zealous for the good at all times—not just when he was with them.
Paul turned to an allegory of Abraham’s two sons to further convince the Galatians of the folly of turning to the Law of Moses. Ishmael was born of a bondwoman and Isaac was born of Abraham’s wife, a freewoman.
A conflict between the two mothers resulted in Hagar and Ishmael being put out of Abraham’s home and sent into the wilderness. Isaac, the son of promise remained with Abraham and was free.
Paul pointed out that Ishmael represented the Law of Moses, the law of bondage. Isaac represented the law of freedom, the new covenant of Christ.
“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.’ So then, brethren, we are not children of the bondwoman but of the free.”