The story of Samudra manthana (churning of the ocean) behind Maha Shivaratri is symbolic for churning of the ocean of consciousness by meditation and other yogic practices. In doing this tapas (spiritual practice) one becomes aware of both the Halāhala (poison of the ego) and Amrit (the nectar of immortality). Both are within us.
When Shiva, the great yogi, saw that the poison of the ego which had come out first from churning of the ocean would destroy the world, he immediately drank it so that others would be protected from harm. As Shiva suffered intense pain from the poison, his wife, the Goddess Parvati touched Shiva’s throat and by the power of her love neutralized the effect of the poison.
The story of Maha Shivratri teaches us that the ego is a powerful poison that can delude the mind and be cause of much destruction. However, pure love, as demonstrated by the Goddess Parvati is overwhelming and can neutralize that poison of the ego and lead to the nectar of immortality. Happy Maha Shivaratri!