There are different rules for citizens who come from the Nordic countries or EU countries.
If a religious worker is a national of Finland, Iceland, Norway and Sweden, no permission is required in order to live and work in Denmark.
Read more about Nordic citizens.
A religious worker who comes from an EU country or from Iceland, Liechtenstein or Switzerland may live and work for up to three months in Denmark without permission. Persons from those countries are known as EU/EEA nationals.
Furthermore, citizens of these countries are allowed to stay for up to six months if they are looking for work. However, this requires a registration certificate.
Read more about the rules for EU/EEA nationals.