Galatians 3:24 - Matthew Poole's English Annotations on the Holy Bible

The law, both the law contained in ordinances and the moral law, was our schoolmaster; serving us in the same stead that a schoolmaster in a school doth, who only fitteth children for higher degrees of learning at universities. To bring us unto Christ: the ceremonial law showed us Christ in all his types and sacrifices; the moral law showed us the absolute need of a Mediator, as it showed us sin, accused and condemned us for it; and it showed us no help either for the guilt of sin contracted, or against the power of it. That we might be justified by faith; so that God's end in giving us the law was, that we might be fitted for Christ, and obtain justification by believing in him.