Lord Ganesha is renowned by his unique image having a big elephant head, pot belly, broken tusk, and a small mouse as vehicle. Ganesh is known as Vignaharta which means destroyer of all obstacles. His long ears signify that he hears every words of his devotees. The elephant head symbolizes wisdom. People in India worship Lord Ganesha before they start any auspicious events like marriage ceremonies, new business venture, moving into a new house, etc. In temples, Lord Ganesh is worshipped before worshipping any other God or Goddess, and there are some specific reasons behind it.
As Per the Scriptures:
According to Ganpati Upanishad, Lord Ganesh appeared even before the creation of purusha (consciousness) and prakriti (nature). That is the main reason why Lord Ganesha is always worshipped first. This scripture says that Lord Ganesha happened prior to the creation of life.
As per the Mythology:
As per legends, when Lord Shiva replaced Ganesha’s head with an elephant head, he gifted Ganesha with many divine powers and declared that Ganesh would be worshipped before starting any auspicious event.
Another legend narrates a story of a race won by Ganesha against his brother Kartikeya. Lord Shiva told Ganesha and Kartikeya to go around the universe and he announced that those who completed the task first would be the winner and he would be worshipped first. Kartikeya sat on his peacock and started the journey around the universe whereas Ganesha walked around his parents, assuming them as the universe. Lord Ganesha was declared the winner and since then he is worshipped before every auspicious event.