Canon Law: TITLE III: GENERAL DECREES AND INSTRUCTIONS
Can. 29 General decrees, by which a competent legislator makes common provisions for a community capable of receiving a law, are true laws and are regulated by the provisions of the canons on laws.
Can. 30 A general decree, as in can. 29, cannot be made by one who has only executive power, unless in particular cases this has been expressly authorized by the competent legislator in accordance with the law, and provided the conditions prescribed in the act of authorization are observed.
Can. 31 §1 Within the limits of their competence, those who have executive power can issue general executory decrees, that is, decrees which define more precisely the manner of applying a law, or which urge the observance of laws.
§2 The provisions of can. 8 are to be observed in regard to the promulgation, and to the interval before the coming into effect, of the decrees mentioned in §1.
Can. 32 General executory decrees which define the manner of application or urge the observance of laws, bind those who are bound by the laws.
Can. 33 §1 General executory decrees, even if published in directories or other such documents, do not derogate from the law, and any of their provisions which are contrary to the law have no force.
§2 These decrees cease to have force by explicit or implicit revocation by the competent authority, and by the cessation of the law for whose execution they were issued. They do not cease on the expiry of the authority of the person who issued them, unless the contrary is expressly provided.
Can. 34 §1 Instructions, namely, which set out the provisions of a law and develop the manner in which it is to be put into effect, are given for the benefit of those whose duty it is to execute the law, and they bind them in executing the law. Those who have executive power may, within the limits of their competence, lawfully publish such instructions.
§2 The regulations of an instruction do not derogate from the law, and if there are any which cannot be reconciled with the provisions of the law they have no force.
§3 Instructions cease to have force not only by explicit or implicit revocation by the
competent authority who published them or by that authority’s superior, but also by the
cessation of the law which they were designed to set out and execute.