Verse23 - Ch 8
By which path one goes to reach Bhagwan after death?. It is Shukla path also known as path of the gods. the other one is the Krishn path also known as the path of the manes,dhum path etc; this path leads one to swarg lok etc where from one returns back to this world after the exhaustion of the punya karma. Shukla, dhum etc. are the presiding deities. Yatra kale,Yasmin kale, here Kal is kala abhimani devata, presiding deity of that path, and not the Time Kal could mean day,night, shukla,krishna paksha, deities which are identified with the deity of that Kal or Path having abhiman (ego) I am this, I-ness. The means (upaya) to achieve the paths could be Karma, it could be Upasana , could be both. Karma Yogi (2) Upasana Yogi yanti, attain anavrittim,the state of non-return; and avrittim, the state of return; chaiva, (which ever path they have practiced). Though in the text,
......all the places of enjoyment,together with the world of Brahma,are subject to return (8.16).
It was stated that those who departed even along the path of the gods return again, still those went along the path of the manes surely return; none of them is fit for gradual liberation.However, some among those who proceeded along the path of the gods return- those who are worshippers of symbols, having reached the ' world of lightning' do return after enjoyment there;those who are performers of meditation on the five fires etc. without being worshippers of Sagun(qualified) Brahman, they, even though led by a non-human person up to Hirnyagarbha, do return after enjoyment there (
see Chandogya Upanisad., 4.15.5; 5.10.2)-, still those who are meditators on Brahman in the 'dahara(small space with in the heart;(see Ch. Upanisad 8.1.2 ),etc.get liberated gradually after enjoyment.Thus not all of them return.
Going through the path of the gods where in the deities mentioned are carriers of the individuals, they do not return. There are the Shrutis,
..... they reach the deity of Flame. From flame they reach day, from day to bright fortnight; from bright fortnight to the six months during which the sun moves northward; from those six months to the year; from the deities of the year to the world of the gods,air,sun, moon, lightning,as also(the gods) Varuna, Indra,and Prajapati. There a non-human person leads them to Brahma. This is the divine path (Chandogya., 5.10.2;Kau.,1.3; Br.,6.2.15 and S's Commentary on B.S.,4.3.2).
This is the path of Brahma. Proceeding along this path, they do not return to this world (Chandogya Up., 4.15.5). Thus, they reach to the conditioned Brahman and through gradual liberation they reach to the unconditioned Brahman at the end of the cycle, on the teachings of the Brahma.
Departing by that path of Manes- smoke, night, dark fortnight, southern solstice-,and reaching the lunar light, the Yogi returns.
Smoke, night etc., are deities who take control of the respective paths. There is the Sruti,
....they reach smoke, from smoke to night,from night to dark fortnight,from fortnight to southern solstice,then to world of manes,from manes to akash,from akash to moon. This is the king of Soma.That is food for gods.Him the gods eat. They enjoy there and after exhaustion of the fruits of good actions, again return along the very path by which they had gone (Chandogya Up,5.10.3-5).
Thus path of non-return is better than this path of return.
Very famous in Shruti and Smriti these two paths are eternal,because transmigratory existence has no begining.By the one of the two, by the white someone goes to the state of non-return;by the other, which is black, all the rest without exception return again. White has effulgent deities while black has dark deities.Other way white stands for Knowledge and the black stands for absence of Knowledge.
Knowing these two paths that one gives libertion and the other to transmigration again no Yogi-Karma yogi and Upashana yogi- gets deluded. He does not pursue selfish actions which lead to the path of smoke. Therefore, O Arjuna, be all time focused .