Worshipping Arunachala is one of the most scared process as Arunachala is the embodiment of the highest form of wisdom of Advaita Vedanata .One need not practise austerities thereafter as he starting moving towards the highest form of Sadhana , where duality is lost and oneness prevails.
More beautiful and strong the idol , more it becomes a bridge for practising the greatest ideal by devotion. In itself , any linga upholds the presence of infinite consciousness in form. And by pure devotion we can reach to state which is manifest.
Nowhere else in the world can one see a linga in the form of a hill. This form constitutes the three gods, Brahma, Vishnu and Siva. It controls the three phases of time as well as the three kinds of powers (saktis). This wonderful Linga is the essence of the three Vedas. Thou abidest on earth in this form as the famous Sonadri (Red Hill) for protecting the three worlds. Even the devas wish to dwell in this abode of Arunachala as there is presence of consciousness , which helps anyone to move in his sadhana faster.
Time being now propitious for Gautama, Gautama have the good fortune of dwelling here. The austerities practised by Gautama have enabled him to see Arunachala. Arunachala’s form is awe-inspiring.
In front of him, Gautama see that form, which he expreses to Gauri – the mother of Universe. It is most auspicious, most compassionate and the refuge of all jivas.
Pray, save me. Sonachala, whom Gautama praised in this manner, revealed thereupon His divine form to him, called him to His side and, after listening to the praises sung with such great devotion, said: “I am greatly pleased with you. You shall worship me according to ancient custom and perform austerities and thus proclaim my glory to all”.
When Gautama were practising austerities on the Kailasa Mountain , Shiva the embodiment of infinite consciousness ordered him to come to the southern country and worship Arunachala.
Like Gautama who is one of the Saptarishis , the Saptarishis worship Arunachala on earth in the same way and do good to all living beings through the power of their austerities.