Verily these bright and dark paths of the world are considered eternal. One leads to non-return, by the other one returns. (Bhagavad Gita 8.26)
No yogi, O son of Pritha, is deluded after knowing these paths. Therefore, O Arjuna, be thou steadfast in yoga, at all times. (Bhagavad Gita 8.27)
These paths, devayana and pitriyana, are part of samsara, and as samsara is eternal, so are these paths. Devayana is the path of light by which go those who seek for wisdom. Its course is marked throughout by bright objects, while pitriyana is the path of darkness, the path of desire and ignorance, and its course is dark all the way. In the Isha Upanishad we find a prayer where Agni (the god of light) is addressed by the departing soul: ‘O Agni (Bright One)! Lead us by the good path. O God! Thou knowest all our deeds, remove all evil from us.’ We must know the two paths and then must live in such a way that we may go by the path of light.
No yogi, O son of Pritha, is deluded after knowing these paths. Therefore, O Arjuna, be thou steadfast in yoga, at all times. (Bhagavad Gita 8.27)
When the yogi has realized in his meditation the distinction between the mortal, perishable body and the immortal Soul, then all thirst for physical life and pleasure vanishes. Then there is no more clinging to material things; the soul thirsts for freedom alone. Knowing that one of the paths leads to samsara, bondage, and the other to moksha, freedom, the yogi takes the path leading to liberation and rejects the other. He is no longer deluded by the thought that heaven is the highest goal and worshipping the gods would save him from rebirth. He knows the result of actions and he also knows that wisdom or love inspired by the highest motives and purest understanding alone leads to the supreme Spirit. Through the bright path he will enter Bliss eternal. Then he is free. But should he choose to return to the world to help humanity, he can do so, knowing the path. He is then conscious of what he does. He is not forced back like others, by the dark path.
Knowledge frees, desire binds. Therefore, O Arjuna, be steadfast in yoga. Be a man, be your own master, be free. Rise above all bondage and then you can choose your own path. Then you will know what you are doing. You need not grope in the dark anymore. It is through yoga that the highest is reached. By single-minded devotion to God alone, we reach the abode of peace. There is none greater than the yogi.