I would recommend Pope John Paul II’s Apostolic Constitution
Sacrae Disciplinae Leges, given to mark the promulgation of the 1983 code of canon law. Of particular note:
*Christ the Lord, indeed, did not in the least wish to destroy the very rich heritage of the Law and of the Prophets which was gradually formed from the history and experience of the People of God in the Old Testament, but He brought it to completion (cf. Mt. 5:17), in such wise that in a new and higher way it became part of the heritage of the New Testament. Therefore, although St. Paul, in expounding the Paschal Mystery, teaches that justification is not obtained by the works of the Law, but by means of faith (cf. Rom. 3:28; Gal. 2:16), he does not thereby exclude the binding force of the Decalogue (cf. Rom. 13:28; Gal. 5:13-25; 6:2), nor does he deny the importance of discipline in the Church of God (cf. 1 Cor. chapters 5, 6). Thus the writings of the New Testament enable us to understand still more the importance itself of discipline and make us see better how it is more closely connected with the saving character of the evangelical message itself.
This being so, it appears sufficiently clear that the Code is in no way intended as a substitute for faith, grace and the charisms in the life of the Church and of the faithful. On the contrary, its purpose is rather to create such an order in the ecclesial society that, while assigning the primacy to faith, grace and the charisms, it at the same time renders easier their organic development in the life both of the ecclesial society and of the individual persons who belong to it.
The Code, as the principal legislative document of the Church, founded on the juridical - legislative heritage of Revelation and Tradition, is to be regarded as an indispensable instrument to ensure order both in individual and social life, and also in the Church’s activity itself. Therefore, besides containing the fundamental elements of the hierarchical and organic structure of the Church as willed by her divine Founder, or as based upon apostolic, or in any case most ancient, tradition, and besides the fundamental principles which govern the exercise of the threefold office entrusted to the Church itself, the Code must also lay down certain rules and norms of behavior. *
See:
vatican.va/holy_father/john_paul_ii/apost_constitutions/documents/hf_jp-ii_apc_25011983_sacrae-disciplinae-leges_en.html
You might be able to extract from this a briefer summary of the role that the code fulfils.