What does Paul mean when he calls the law a schoolmaster?
The law served as a hired servant assigned to train and prepare Israel, bringing them to readiness for the Messiah. It was not meant to make them full sons, but to prepare them so that, when Christ came, they could enter full sonship by faith.
Les explains that Paul’s term “schoolmaster” pictures a servant who had been hired and instructed to bring the child to the place where he could step right in and work with the father. The Scripture word “adoption” did not mean taking a child from another union, but being placed as a full operating son, equal with the Father in responsibility and function. That is the term Paul is using as a schoolmaster. The Law was intended to do that for Israel: to prepare them, and prepare them, until the Messiah would come, so they were ready and in faith could have said yes. A few did, but for the most part the nation rejected it. Les carries the concept over into the Gentile economy: the Law was given to prepare everything for the coming of the Messiah, that He could fulfill the work of the Cross—He had to die, be buried, and be raised for our justification.