The 28-year-old won the European Championship in 2008 and 2012 and the World Cup in South Africa in 2010 with La Furia Roja.
"It's massive, especially because it is in Brazil with all that means," he told The Guardian. "A World Cup in Brazil is unique.
"It could be that after winning two European Championships and the World Cup, when maybe you would think there would be nothing else to strive for, this is a gift. Something to fight for.
"Another title and an achievement that would be very, very special."
Spain are currently at the top of Group I in the 2014 World Cup qualifying campaign with seven points from three matches.