The first passage of this story basically describes the building of Heorot. Hrothgar, decides to build a Valhalla-type of sanctuary for his warriors that he names "Heorot", or the Hall of the Hart (deer hall). This is in the first main passage of the story of Beowulf and this is the first place we find the theme of internal versus external evil. The passage implies that internal evil will ultimately destroy the hall, rather than being attacked by monsters: "The hall stood tall, high and wide-gabled: it would wait fierce flames of vengeful fire: the time was not yet at hand for sword-hate between son-in-law and father-in-law to awaken after murderous rage. "(Norton 28) This foreshadows the internal evil that will destroy the Danes. Another theme in this story is the theme of men versus monsters. This theme comes to light when Grendel is described: "The creature of evil, grim and fierce, was quickly ready, savage and cruel, and seized from their rest thirty thanes".(Norton 28)
Heorot is a drinking hall, where warriors gather for parties and to get drunk. Heorot is a creation of civilization made by Hrothgar, for men to gather as a meeting place and a place to sleep. Hrothgar builds the biggest hall ever made. Grendel then attacks the hall for twelve winters straight, destroying more and more men every night with no remorse, and the men are afraid to sleep in the hall, thinking that maybe Grendel will eat them. Grendel is a ruthless caniball: "I think that if he may accomplish it, unafraid he will feed on the folk of the Geats in the war-hall as he has often done on the flower of men."(Norton 32-33)
References: were made to Beowulf before this point. He was built up to being a super hero and here is where he makes his first appearance. Abrams, M. H. et al., The Norton Anthology of English Literature. Volume 1. 6th Edition. New York: W.W Norton & Company, 1993.