Once the question arose among the gods of who should be worshipped first. Shiva and Parvati set a contest between their two sons, Ganesha and Kartikeya: whoever circled the entire earth and returned first would be the winner.
Kartikeya at once mounted his peacock and flew off. Ganesha's vehicle was a tiny mouse, but he had wonderful wisdom.
Ganesha seated his parents and, with deep devotion, walked around them seven times. Then he said: "For me, my mother and father are the whole world." Shiva and Parvati were delighted and declared Ganesha the winner. This story teaches that serving one's parents is the greatest pilgrimage of all.