"Frailty, thy name is woman!" (Act I, Scene II)
Hamlet is referring to his mother when he says woman, he believes that her quick marriage to his uncle is a sign of her weakness. Hamlet felt she was weak, or not strong enough to mourn his father longer. Hamlet goes on further to say that not even an animal or beast, who has no reasoning skills, would have abandoned the mourning so quickly. In all of this he shows how angry and confused Hamlet is by his mother's remarriage. He actually indicates that nothing good can come from this action. This does foreshadow a few things, one of the things is the death of Ophelia, who succumbs to her own grief and confusion and is drowned. Also, the death of Gertrude herself, her marriage to Claudius did bring this about, as she mistakenly drank the cup he poisoned for Hamlet.