Balder represents a type of the "Dying God," a figure that's very common in world religions and mythologies. This god is one who dies and is reborn, sometimes cyclically. Often, his rebirth ushers in a new period of fertility, or even a new, better world.
One of the most famous of these gods is Jesus, whose death on a cross and subsequent return from Hell ushers in a new era in which, Christians believe, they, too, can attain eternal life. Like Balder's, Jesus' death and resurrection are prophesied, as is his return at the end of the earthly world to rule over a new, better one.
Some people believe that the precursor (the one who came before) to Jesus in Middle Eastern religions was Osiris, the Egyptian god who, like Balder, was killed by his own brother. His sister/wife Isis managed to revive him sufficiently to conceive a son who, like Balder's brother, Vali, was prophesied to return and avenge his brother/father. Isis buried the pieces of Osiris's body all over Egypt, ensuring the fertility of the land forever, thus giving eternal life which in this story is physical rather than spiritual.
Persephone is also a kind of "Dying God" in Greek mythology. Persephone is the daughter of Demeter, goddess of the harvest. Persephone was kidnapped by her uncle, Hades, who is the god of the underworld. As a result, she is forced to spend half of the year in the underworld, during which time Demeter lets nothing grow on earth. For the other half of the year, Persephone is allowed to return home to her mother, bringing spring with her.
You can read all about Persephone in the myth of Persephone, Demeter, and Hades.