If such is the case, is the law, then, an anti-promise, a negation of God's will for us? Not at all. Its purpose was to make obvious to everyone that we are, in ourselves, out of right relationship with God, and therefore to show us the futility of devising some religious system for getting by our own efforts what we can only get by waiting in faith for God to complete his promise. For if any kind of rule-keeping had power to create life in us, we would certainly have gotten it by this time.
Until the time when we were mature enough to respond freely in faith to the living God, we were carefully surrounded and protected by the Mosaic law.
The law was like those Greek tutors, with which you are familiar, who escort children to school and protect them from danger or distraction, making sure the children will really get to the place they set out for.
But now you have arrived at your destination:
By faith in Christ you are in direct relationship with God.
Your baptism in Christ was not just washing you up for a fresh start. It also involved dressing you in an adult faith wardrobe - Christ's life, the fulfillment of God's original promise.
In Christ's family there can be no division into Jew and non-Jew, slave and free, male and female. Among us you are all equal. That is, we are all in a common relationship with Jesus Christ.
Also, since you are Christ's family, then you are Abraham's famous "descendant," heirs according to the covenant promises.