How do the pagan and Christian elements come out to play in this piece?

Although not always overt, there are many clues that we can follow regarding Christian and Pagan beliefs in Beowulf. Consider that the people mention the g-d (that's in singular form used) of war and they pray that he will be on their side and help them defeat the big mean dragon. This idea of a God of war supports pagan ideas for separate Gods for separate purposes. Certainly monsters and dragons support pagan ideas of evil. A cross is mentioned in the context of God which supports a Christian ideal. Also Grendel’s mother is described as being descended from Cain which is directly related to the Old Testament.