The Ribhu Gita/(Sixth Amsa Of Siva Rahasyam)
Shivarahasya Purana (Sanskrit: ; IAST: iva rahasya pur a) is one of the 'Shaiva Upapuranas' or ancillary Purana regarding Shiva and Shaivite worship and is also considered 'Indian epic poetry' (Sanskrit: Itih sa).Its origins are acclaimed to be over 7000 years old.It is one of the first few works of the acclaimed Saint Ribhu, who was taught by Shiva himself. The Ribhu Gita (Sanskrit: ; IAST: bhug t ) is an acclaimed advaita, monist and/or nondual song at the heart of this Purana. --Wikipedia