24 And here is precisely the ground on which, political dissensions aside, upright men should unite as one to combat, by all lawful and honest means, these progressive abuses of legislation. The respect due to constituted power cannot prohibit this: unlimited respect and obedience cannot be yielded to all legislative measures, of no matter what kind, enacted by this same power. Let it not be forgotten that law is a precept ordained according to reason and promulgated for the good of the community by those who, for this end, have been entrusted with power... Accordingly, such points in legislation as are hostile to religion and to God should never be approved; to the contrary, it is a duty to disapprove them. It was this that St. Augustine, the great Bishop of Hippo, brought out so strongly in his eloquent reasoning: "Sometimes the powerful ones of earth are good and fear God; at other times they fear Him not. Julian was an emperor unfaithful to God, an apostate, a pervert, an idolator. Christian soldiers served this faithless emperor, but as soon as there was question of the cause of Jesus Christ they recognized only Him who was in heaven. Julian commanded them to honor idols and offer them incense, but they put God above the prince. However, when he made them form into ranks and march against a hostile nation, they obeyed instantly. They distinguished the eternal from the temporal master and still in view of the eternal Master they submitted to such a temporal master."(10)
Source: Au Milieu Des Sollicitudes (Vatican.va)