Given that the epic poem Beowulf was written from a Christian perspective, God (or the divine being) is regarded with the utmost respect. Throughout the poem, many references are made to the belief that God has his hand in all which happens. Heroes are not able to win epic battles without God's nod of approval.
In chapter one (if using the E-Text), Hrothgar is wanting to build a mead hall which will give glory to God. Hrothgar realizes that everything that he possess is because God has allowed him to.
Therein would he bestow to young and old all that the Lord should give him, save people's land and the lives of men.
In chapter seven, Hrothgar again states that God is the ultimate authority.
But God is able to halt the deeds of this deadly fiend!
Here, Hrothgar knows that God is in charge of all. Hrothgar also reveals the fact that God is the one who will be awarded the victory over Grendel, not necessarily the warrior who meets the monster in an epic battle. (One way to look at this is as if Beowulf is an extension of God--the and which will take the arm of the monster.)
The feelings, and faith, of the Geats (through Beowulf) is best stated in chapter ten:
In truth, the prince of the Geats gladly trusted in his valorous might and the mercy of God! It is said truly by all that God has ever governed over mankind!
Based upon this, there is no question about the faith of the Geats.
In the end, the Danes' and Geats' faith in God is unquestionable. Both clans realize that God has power over all.