A question about practising Christianity against authority Romans 13:1-2 (RSV)


  1 Let every person be subject to the governing authorities. For there is no authority except from God, and those that exist have been instituted by God. 2 Therefore he who resists the authorities resists what God has appointed, and those who resist will incur judgment.


Suppose a government legally forbids their citizens to practise Christianity (i.e. Catholicism, Protestantism, etc.). According to the verses above, would someone who practises Christianity in this context be resisting God?
No. Christians who live under the authority of a government that outlaws Christianity would not be resisting God by refusing to abandon their faith. One might imagine that the right thing to do is to obey such laws, perhaps crossing the border to go to church. This is not the case. Authority exercised against the common good is authority that has broken down completely. There is no authority, and Christians are in no way bound by the unjust laws of a government that has no authority.
The Catechism has an article on this subject, part of which addresses governing authority that forbids freedom of religion. (Other major denominations have similar teachings, justified in effectively the same way). The particular sections:

1903 Authority is exercised legitimately only when it seeks the common good of the group concerned and if it employs morally licit means to attain it. If rulers were to enact unjust laws or take measures contrary to the moral order, such arrangements would not be binding in conscience. In such a case, &quot;authority breaks down completely and results in shameful abuse.&quot;
1906 By common good is to be understood &quot;the sum total of social conditions which allow people, either as groups or as individuals, to reach their fulfillment more fully and more easily.&quot;26 The common good concerns the life of all. It calls for prudence from each, and even more from those who exercise the office of authority. It consists of three essential elements: [...]

These elements are the respect for the person, the social well-being and development of the group itself, and peace. The first element, respect for the person:

1907 First, the common good presupposes respect for the person as such. In the name of the common good, public authorities are bound to respect the fundamental and inalienable rights of the human person. Society should permit each of its members to fulfill his vocation. In particular, the common good resides in the conditions for the exercise of the natural freedoms indispensable for the development of the human vocation, such as &quot;the right to act according to a sound norm of conscience and to safeguard . . . privacy, and rightful freedom also in matters of religion.&quot;

This view goes back to the earliest days of Christianity. During times of persecution, Masses were offered up to God in secret places while Christians were fed to lions and set on fire to provide lighting for festive events. Many refused even under torture and threat of death to renounce their beliefs, and were martyred for their faith in God.