“But what does the Scripture say? ‘Cast out the slave woman and her son, for the son of the slave woman shall not inherit with the son of the free woman.'” (Gal. 4:30)
Keep in mind how Paul is using this story of Ishmael and Isaac. His comparison began with the two mothers, one of whom was free and one of whom was in slavery. He has paired the slave woman and her son with the law and the free woman and her son with the promise. The purpose of this comparison is to show the difference between the two systems of salvation being considered in this book.
The system of law is represented by the slave woman and the system of grace is represented by the free one. By comparing the two women Paul hopes to explain the two systems. We already know that Paul sees one as good and one as bad. We already know that Paul is astonished that the subject of a system of law salvation would even come up and that when it did the Galatians who had started with grace would give that unworkable system a hearing but that is exactly what they have done.
Paul wishes to impart the knowledge to the Galatians and the Judaizers that the system of law they have reference to is no longer a workable solution to sin if indeed it ever was. Just as Hagar was driven out from Abraham’s camp so the system of law has to go. “Cast it out,” is Paul’s take on the law. There is only one inheritance and only one of the two sons can inherit it. Paul has used Sarah’s words to dismiss the law the Judaizers were trying to rescue. We know that Abraham was not pleased with this order of Sarah’s. He wasn’t in favor of removing Ishmael but God intervened and told him, “Whatever Sarah says to you do as she tells you…” We can understand then the reluctance of the Judaizers to give up the law. Just as Abraham wanted to keep the slave son so the Jews wanted to keep the law.
The truth is that God sent the slave woman and her son into the desert area and He replaced the law of Moses with the grace of Jesus. It’s that simple but many people, including many church groups, want to keep the system of law around. Whether it is the act of circumcision or keeping the Sabbath or observing a feast, once that becomes mandatory for salvation the entire system of law is invoked. Do one, do all and if you do one and then all you must give up grace.
Task for Today: Please don’t give up grace. You started by grace, continue in grace. Let it abound. Trust grace, trust Jesus, trust God. What you have freely received, pass on to others. Make no demands of yourself or others than to love God with all your being and others as yourself.