Wherefore the law was our schoolmaster - The word rendered schoolmaster (παιδαγωγὸς paidagōgos, whence the word “pedagogue”), referred originally to a slave or freedman, to whose care boys were committed, and who accompanied them to the public schools. The idea here is not that of instructor, but there is reference to the office and duty of the “paedagogus” among the ancients. The office was usually intrusted to slaves or freedmen. It is true, that when the “paedagogus” was properly qualified, he assisted the children committed to his care in preparing their lessons. But still his main duty was not instruction, but it was to watch over the boys; to restrain them from evil and temptation; and to conduct them to the schools, where they might receive instruction. See, for illustrations of this, Wetstein, Bloomfield, etc. In the passage before us, the proper notion of pedagogue is retained. In our sense of the word schoolmaster, Christ is the schoolmaster, and not the Law. The Law performs the office of the ancient pedagogue, to lead us to the teacher or the instructor. That teacher or instructor is Christ. The ways in which the Law does this may be the following:
(1) It restrains us and rebukes us, and keeps us as the ancient pedagogue did his boys.
(2) The whole law was designed to be introductory to Christ. The sacrifices and offerings were designed to shadow forth the Messiah, and to introduce him to the world.
(3) The moral law - the Law of God - shows people their sin and danger, and thus leads them to the Saviour. It condemns them, and thus prepares them to welcome the offer of pardon through a Redeemer.
(4) It still does this. The whole economy of the Jews was designed to do this and under the preaching of the gospel it is still done. People see that they are condemned; they are convinced by the Law that they cannot save themselves, and thus they are led to the Redeemer. The effect of the preached gospel is to show people their sins, and thus to be preparatory to the embracing of the offer of pardon. Hence, the importance of preaching the Law still; and hence, it is needful that people should be made to feel that they are sinners, in order that they may be prepared to embrace the offers of mercy; compare the note at Romans 10:4.