The Sacred Story of Ganesh Puja
According to the Shiva Purana, Goddess Parvati created Ganesha from the sandalwood paste she used for her bath. She breathed life into him and assigned him to guard her door while she bathed. When Lord Shiva returned, Ganesha, unaware of who he was, denied him entry. Enraged, Shiva severed his head.
Seeing Parvati's grief, Shiva promised to bring Ganesha back to life. He sent his ganas to bring the head of the first living creature they found facing north. They returned with the head of an elephant. Shiva placed it on Ganesha's body and restored him to life, granting him the boon that he would be worshipped before all deities in any ritual.
Thus, Ganesh Puja became the foremost ritual. Another popular legend from the Ganesh Chaturthi tradition speaks of the 21-day penance performed by a boy named Gana, who pleased Lord Ganesha and received the boon of walking again, establishing the power of dedicated Ganesh worship.
"From that day onward, whoever performs Ganesh Puja with pure devotion will have all obstacles removed and their righteous desires fulfilled." — Shiva Purana