I remember when our first child, Alyssa got on the school bus for her first day of Kindergarten. It was a rather emotional moment for us. After Carol and I got her ready and had breakfast with her, the three of us walked down the street to wait at the corner. Finally, the bus came; she gave us a hug and a kiss and entered through the door of the bus, found a seat, and off she went to her first day of school. For the first time in her young life we were literally entrusting our much beloved daughter to someone else-- the school bus driver-- whose job it was to make sure Alyssa and all the children in her charge arrived safely to their destination where the responsibility for her care would be transferred to her teacher. With the children safely in school the job of the driver had been fulfilled and she had discharged her duties faithfully.
Paul in essence says the same thing about the law in Galatians. He says that we "were imprisoned and guarded under the law until faith should be revealed." The King James incorrectly refers to the law as our schoolmaster; but the purpose of the law in this analogy was to get us to school until Christ would come. The law is not the teacher at school, it is school bus driver on the way to school. Now that Christ has come school is in session and the law's charge has been fulfilled. In Galatians, Paul sees the law of Moses as an interim covenant, as a bridge between the covenant with Abraham and the covenant with Jesus Christ. Paul refers to the law as our pedagogue, the slave whose task was to get the children to school safely. Don Garlington writes,
This "disciplinarian" or "custodian" was a slave who had charge of a young boy, at least into late adolescence. He was not so much a teacher as one who led a youth to and from school and saw to his care, protection and discipline. For many youths, their experience of the pedagogue could be decidedly unpleasant, and most were probably glad to be rid of their taskmasters. Nevertheless, the pedagogue did serve a useful purpose, and by drawing on the imagery of the disciplinarian, Paul casts the law in just this light.It is unfortunate that Christians have too often interpreted Paul's language of being imprisoned under the law negatively. What Paul has in mind here is not being in prison for a crime committed, but rather protective custody where the individual is being guarded in order to protect them. The law was given for our own good, to keep us on the right path until Christ would come.
For Paul, now that Christ has come it is the response of faith based on the faithfulness of Jesus Christ to his to his work that puts one into the covenant. Observance of the law, particularly its practices that marked out Jews as the people of God (i.e. circumcision, food laws, Sabbath observance) were not required for the Gentiles to be God's people. Ben Witherington notes that in chapters three and four that when Paul uses the pronoun "we" he is referring to the Jews under the law as well as himself before his conversion. "You" denotes the Gentiles who have come to faith in Jesus. "Paul is indeed arguing that salvation brought by Christ came to the Jews first, but also that it came to them so that they might fulfill their proper role of being a light to the Gentiles" (Witherington, Galatians, p. 267).
Jesus Christ has now put Jews and Gentiles on equal footing in the covenant. Gentiles no longer have to proselytize-- to be come Jews in a sense-- to share in the promises of the covenant God made to Abraham. The faithfulness of Jesus Christ makes the response of faith in Christ all that is necessary.
It is critical to note that having faith in Christ does not excludes faithfulness to Christ, but necessitates it. Paul has no such dichotomy in mind. To have faith in Christ is not just notional assent; it includes assent to the moral life Jesus calls his followers to embody. All one has to do is read the rest of the letter to know that.
In Christ, God's promise to Abraham has been fulfilled-- "I will indeed bless you, and I will make your offspring as numerous as the stars of heaven and as the sand that is on the seashore. And your offspring shall possess the gate of their enemies, and by your offspring shall all the nations of the earth gain blessing for themselves, because you have obeyed my voice" (Genesis 22:17-18).
As Abraham obeyed God's voice, now in Jesus Christ his followers must obey that same voice which has now decisively spoken in Jesus Christ.