Blasphemy and cursing the name of G-d
(Affirmatively stated: Reverence for G-d; serving G-d)
Distinct from, though closely related to, the Noahide laws relating to the belief in G-d (centering on the prohibition on idolatry), is a law relating generally to the reverence for G-d. This law is also foundational to the Noahide laws: just as belief in G-d is the basis of the authority of the other Noahide laws, so reverence to G-d translates belief into practice and establishes firmness and integrity of conscience in ethical conduct. Its scope ranges from prohibition on blasphemy, the ultimate irreverence for G-d. These levels in this precept are here set out as a sequence, each with its individual laws and sources.
One commentator writes that blasphemy (the prohibition of which forms the first topic in the reverence for G-d) is a deeper transgression that idolatry. For whilst the idolater "adds" a deity, the blasphemer attacks G-d Himself. Blasphemy is the verbal act of one who knows G-d and yet rebels against ("curse") Him. Hence, this is the ultimate irreverence: that, which in the understanding of the blasphemer is deserving of the reverence, is yet treated with extreme disrespect. The blasphemer, "knowing G-d" and having no "principled" rejection of G-d, yet blasphemes out of sub-rational personal desires, resentments or passions.
In the spectrum of the precept of reverence for G-d, after the prohibition of blasphemy with its rebellion against G-d, comes an injunction to "fear" G-d, i.e. to treat G-d with respect. Minimally, this applies negatively: not to treat G-d with disrespect. Respect is due to the Name of G-d, when it is spoken in an oath. This has traditionally been the means taken to assure the truthfulness of oaths taken with G-d's Name. The assumption is that an oath, involving G-d's Name, would not be spoken falsely out of respect for G-d, whose "truth" is associated with the claimed truthfulness of a sworn statement.
Respect for G-d extends to the written Names of G-d and also to sacred texts which contain Divine teaching (even if they do not contain written Names of G-d). Mistreatment (such as effacement) of these is disrespect for that to which they refer or relate: G-d. After this comes the respect due to those who (and because they) are in various degrees conduits for the Divine teaching, such as prophets and teachers of the Divine law, and great spiritual leaders, whose holiness is some sense a "reflection" of the Divine.
All of the above are related to the reverence for G-d Himself. At a further remove, is the honor, or prohibition of disrespect, for that which is "associated" with G-d. Such is the respect to to parents (G-d's "partners" in the creation of the human being) and to the human being in general, who spiritually is stamped with "image of G-d".
For the negation of irreverence- the prohibition of blasphemy and disrespect- for the Divine and for that assiocated with the Divine, one comes to the positive service of G-d. The services of G-d, which motivates one to fulfill all Divine precepts, is expressed particularly in prayer, the study of the Noahide law, and repentance. This is active reverence for G-d. In summary, the division of this topic follows the successive stages: (B) the prohibition of blasphemy (C) respect for the Divine (D) honoring one's parents and persons and one's word and (E) the service of G-d in prayer, the study of the Divine teaching, and repentance.
Rabbi Dr. Shimon Cowen, The Theory & Practice of Universal Ethics: The Noahide Laws, Institute for Judaism and Civilization, Melbourne & New York, 2014, pgs. 192-194