It is illegal in UK elections to invoke god. Similarly, any endorsement by a priest, imam etc is forbidden.I was thinking more of places like India, certain African countries, Iran, Saudi etc
Obviously god is not mentioned at election time in the UK. Blair's spin doctor Alastair Campbell famously advised when George Bush wanted to meet Tony in a cathedral, 'we don't do god'.
Religious parties were banned in Turkey until Erdogan came along and changed the constitution. Not sure about EU.