Dvořák was born in 1841 in Nelahozeves, near Prague, in the Austrian Empire, to František Dvořák and his wife, Anna as the first of 14 children, eight of whom survived infancy.Dvořák was baptized as a Roman Catholic in the village's church of St. Andrew. Dvořák's years in Nelahozeves nurtured his strong Christian faith and the love for his Bohemian heritage that so strongly influenced his music. He was organist at St.Adalbert Church in Prague from 1874 to 1877.
Your hypothesis that a plagal cadence implies a Christian belief has already been discussed in this question. I provided two counterexamples: Felix Mendelssohn, who was Jewish, wrote plagal cadences at the end of his overture to "A Midsummer Night's Dream" and at the end of the first movement of his 5th Symphony ("Reformation Symphony").