Beowulf is noteworthy as the oldest surviving major work composed in English, although if we were to attempt to read it in its original form, Old English, we would find it incomprehensible, because the language has changed so much since the poem was composed about 14 centuries ago.
In those days, England was still in a state of religious transition, moving from the old pagan mythologies of the Celts and Anglo-Saxons to Christianity, which was spreading in Europe in Asia. However, such major changes don’t occur instantly, so we see in Beowulf a confluence of Christianity and paganism.
There are several instances in Beowulf that demonstrate this evolution. At one point, the Danes, in their fear over Grendel’s murderous rampage revert to paganism:
And sometimes they sacrificed to the old stone gods,
Made heathen vows, hoping for Hell’s
Support, the Devil’s guidance in driving
Their affliction off.
We also see that Grendel himself has the paganistic power of sorcery, as he able to cast a spell to help him terrorize the Danes:
. . . for that sin-stained demon
Had bewitched all men’s weapons, laid spells
That blunted every mortal man’s blade.
Such a power implies that the people of this time were willing to accept, and in many cases probably believe, that certain individuals have the power to cast spells.
Finally, the story shows that God is able and willing to intervene miraculously, in some cases, to help his followers. In those days, and for quite a long time afterward, it was generally accepted that kings were appointed by God. Hrothgar, king of the Danes, has a throne that Grendel is unable to attack, because he was prevented from doing so by God:
Though he lived in Herot, when the night hid him, he never
Dared to touch king Hrothgar’s glorious
Throne, protected by God—God,
whose love Grendel could not know.
Hrothgar's throne is protected by God so Grendel cannot touch it because Grendel, a monster born of a pair of monsters who were decended from Cain, cannot know God's love. The story is a mix of paganism and Christianity because the Christian faith was beginning to spread across the land but people hadn't fully relinquished their paganistic beliefs yet. The Christian references are full of reverence and mystery because the faith was new to people.