Balder was the favorite son of Odin and Frigg.Baldr has been having nightmares. Odin rides to Hel to investigate. He finds the grave of a Volva and resurrects her. Their conversation follows, where the völva tells Odin about Baldr's fate. In the end Odin asks her a question which reveals his identity and thevölva tells him to ride home.
Actually Friggs also having this dream where it is symbolised as Baldr's death. As we a know, Baldr was her beloved son and she was extremly sad of this sign.