Hari (Sanskrit: हरि) is among the primary epithets of the Hindu preserver deity Vishnu, meaning 'the one who takes away' (sins). It refers to the one who removes darkness and illusion, the one who removes all obstacles to spiritual progress. In the Rigveda’s Purusha Sukta (praise of the supreme cosmic being), Hari is the first and most important name of the supreme Divine Being (whose Sanskrit cognate is Brahman). The second and alternative name of the supreme being is Narayana according to Narayana sukta of the Yajurveda. Within the Hindu tradition, it is often used interchangeably with Vishnu to such an extent that they are considered to be one and the same. The name "Hari" also appears as the 656th name of Vishnu in the Vishnu Sahasranama of the Mahabharata and is considered to be of great significance in Vaishnavism. In the Vedas, it is required to use the mantra "Harih om" before any recitation, just to declare that every ritual we perform is an offering to that supreme Divine Being; even if the hymn praises some one or the other demigods. The idea of demigods as found in Hinduism is very different from that found within Greco-Roman mythology. This has to be borne in mind while understanding how, within Hinduism, all beings including demigods are inseparable from Hari. Hari in Purusha Suktam, Narayana Suktam and Rudra Suktam is usually depicted as having a form with countless heads, limbs and arms (a way of saying that the Supreme Being is everywhere and cannot be limited by conditional aspects of time and space). Lord Hari is also called Sharangapani as he also wields a bow named as Sharanga.