Last time Paul had begun to explain the purpose of the Law and its relationship to salvation by grace through faith. He continued with this:
Galatians 3:21b-29 (KJV)
21 for if there had been a law given which could have given life, verily righteousness should have been by the law.
But the scripture hath concluded all under sin, that the promise by faith of Jesus Christ might be given to them that believe.
But before faith came, we were kept under the law, shut up unto the faith which should afterwards be revealed.
Wherefore the law was our schoolmaster to bring us unto Christ, that we might be justified by faith.
But after that faith is come, we are no longer under a schoolmaster.
For ye are all the children of God by faith in Christ Jesus.
For as many of you as have been baptized into Christ have put on Christ.
There is neither Jew nor Greek, there is neither bond nor free, there is neither male nor female: for ye are all one in Christ Jesus.
And if ye be Christ's, then are ye Abraham's seed, and heirs according to the promise.
In verse 21b Paul went on to say that if the Law could give life, then righteousness or salvation would have been by the Law. However, he pointed out that because of the Law, it is obvious that all mankind is sinful (verse 22). The promise of salvation given by faith in Yeshua is only given to them that believe. But before a believer comes to faith he or she is "guarded" (Aramaic English New Testament by Andrew Roth) by the Torah (verse 23). Paul was saying that before faith, mankind's only way of living is by staying within the confines of the written Law. When faith comes, Torah is moved internally and the Holy Spirit's power is there to help the believer live according to the Law.
Verse 24 summarized what Paul had been saying. The Law is the schoolmaster that convicts mankind of sin, thereby bringing them to desire a remedy, which is repentance and then faith in Yeshua's work on the cross. The believer is then justified by that faith. After faith, a believer is no longer under the schoolmaster (verse 25). Since the Torah has been internalized, obedience is possible by the Holy Spirit. The condemnation that the schoolmaster brought is no longer there. But it is the condemnation of the Torah that is gone, not the Torah itself.
Paul then went back to his initial argument in verse 26 that through faith in Yeshua the believing Galatians were the children of God and by baptism had put on Yeshua's righteousness like a garment (Aramaic English New Testament) (verse 27). Therefore, there is only the body of Yeshua, not separate groups of Jews or Gentiles (Greeks), slaves or free born members, nor males or females. All are one in Yeshua (verse 28). And if they are all Yeshua's then they all are Abraham's descendants and heirs according to the promise of salvation by grace through faith (verse 29).
All Christians agree that the purpose of the Torah initially is as a schoolmaster. Traditional Christianity then says that once Yeshua came, the Torah was no longer needed as a schoolmaster, since Yeshua fulfilled the Torah. Therefore, no one needs to observe the Torah any more. However, if Galatians had been written with that intent, the purpose of the Torah is removed. How do unbelievers come to Yeshua? There would be no source of conviction! The Torah must continue in force.
Some Christians believe that the Ten Commandments or those laws from the Torah that are repeated in the New Testament can now function as the schoolmaster. This is only partially true. Paul made no such distinctions and this thinking only allows believers and unbelievers alike to violate the Torah as a whole.