Pacem in Terris §51

⁵¹ Governmental authority, therefore, is a postulate of the moral order and derives from God. Consequently, laws and decrees passed in contravention of the moral order, and hence of the divine will, can have no binding force in conscience, since "it is right to obey God rather than men "(34). Indeed, the passing of such laws undermines the very nature of authority and results in shameful abuse. As St. Thomas teaches, "In regard to the second proposition, we maintain that human law has the rationale of law in so far as it is in accordance with right reason, and as such it obviously derives from eternal law. A law which is at variance with reason is to that extent unjust and has no longer the rationale of law. It is rather an act of violence."(35)