"Brethren, I speak in terms of human relations: even though it is only a man's covenant, yet when it has been ratified, no one sets it aside or adds conditions to it. Now the promises were spoken to Abraham and to his seed. He does not say, 'And to seeds,' as referring to many, but rather to one, 'And to your seed,' that is, Christ. What I am saying is this: the Law, which came four hundred and thirty years later, does not invalidate a covenant previously ratified by God, so as to nullify the promise. For if the inheritance is based on law, it is no longer based on a promise; but God has granted it to Abraham by means of a promise." (Galatians 3:15-18)Paul is beginning to setup his position on the Law and the Christian's relationship to it. What must be understood is that, while the law was important and necessary, it was not the main event. It stood as an intermediary, an interlude, between the promises made to Abraham and their fulfillment in Christ. The Law was never intended to be the fulfillment of the Abrahamic promises nor did it serve to modify or nullify those promises.
As Christians we sometimes misunderstand the promises and message of God because we view them through the lens of the Law. We see the promises made to Abraham but we see them through the intervening years in which the Law was in effect. Sometimes, it is hard to understand our redemption without reference to the Law. How can one be redeemed and walk as a Christina and yet not keep the Law as given by God? For some, this leads them from grace back into the bondage of the Law. For others, it causes them to try and mix law and grace. These, while calming to be Christian, seem to be desiring to become Jewish, maintaining their law, feasts, and customs. However, God has not called us to be Jewish but to be Christ-like. The Christian walk is not a walk back to becoming Jewish but a walk forward into the blessing and freedom God previously promised to Abraham.
The Galatians, while trying to add elements of the Law to their faith, were in reality re-building the wall that separated them from the blessings and promises of Abraham. Later on, Paul will warn them, "You have been severed from Christ, you who are seeking to be justified by law; you have fallen from grace." (Galatians 5:4) The law and grace are incompatible; we must choose one or the other. John put it this way, "For the Law was given through Moses; grace and truth were realized through Jesus Christ." (John 1:17) One is not found in the other, we must choose which font we will drink from. Either the font of Moses bringing the law or the font of Jesus bringing us grace and truth.
We are a people of covenant, a covenant made with Abraham and those descended from "his seed". Let us not get caught up in the trappings of the Law but live the life of freedom we have in Christ and in His grace. Let us choose Grace not re-immersion back into law.