“…For what use is the law revealed? I answer…To them that are in Christ. It serves,
[1.] To magnify Christ unto them, shewing them their obligation to him for fulfilling it in their stead. ‘O wretched man that I am! (says the apostle); who shall deliver me from the body of this death? I thank God, through Jesus Christ our Lord,’ Rom. vii. 24, 25. ‘Christ hath redeemed us from the curse of the law, being made a curse for us: for it is written, cursed is every one that hangeth on a tree; that the blessing of Abraham might come on the Gentiles through Jesus Christ; that we might receive the promise of the Spirit through faith,’ Gal. iii. 13, 14.
[2.] To be a rule of life unto them, wherein they may express their gratitude by obeying the law of Christ. So the law leads to Christ as a Redeemer from its curse and condemnation, and He leads back to the law as a directory, the rule and standard of their obedience to him.
Works of Thomas Boston, vol. 2, “The Moral Law,” pp. 64-65