And that the sunyavadis merge into the brahmajyoti effulgence.
The brahmajyoti effulgence is the shining light of God's Face-body-smile-energy-personality-splendor.
The entire creation, the spiritual eternal kingdom of God and the present material transcient universe eminates from God's Body.
The spiritual realm where God is King and Lord and Master and benefactor is eternal. Eternality is a shining feature of God's definition.
The shining light of God's Person is the well known destination of the Yogis and Hindu ascetics, the destination of the Yogis and Hindu ascetics who do not seek nor believe in the devotional service to Godhead.
Excluded from the above non-theist Yogis and Hindu ascetics are the adherents of the 'karma kanda' sections of Hindu scripture. The 'karma kanda' sections of Hindu scripture are about achieving 'desirables' so that Fruitive endeavors are always the pursuit of 'karma kanda' hindus.
This is the essence of the Bhagavad-gita's message for Theists.
When Krishna uses the words "Unsuccessful Yogi", Krishna is referring to those that achieved celestial rewards and also to the Yogi that merged into the Brahmajyoti or and any type of nirvana like state.
Since the the Bhagavad-gita defines that the 'Soul is alway active by nature', it is affirmed by Krishna that the soul cannot say desireless indefiniately, so the soul will returns to the world of fruitive activity inorder to enjoy sense pleasure as a means of living, instead of remaining in a dormant inert quasi-sleep state commonly known as nirvana.
Of course there in mention in the gitas of the un-successful yogi that, after enjoying the fruits of good karma amongst vast life times in the celestial higher planetary systems (of the devas), when the fruitive good karma (karma-kanda) is expended, such a yogi retruns to the terrestrial planetary systems to engage in fruitive goals yet again.
If such yogis had continued to be thoughtfull and adverse to doing bad-karmic activities, they may be lucky enough to resume the yogi path again. This is how samsara and karma can be so impersonal.
Here is the actual verse.
Bg 6.41
The unsuccessful yogi, after many, many years of enjoyment on the planets of the pious living entities, is born into a family of righteous people, or into a family of rich aristocracy.
As A.C. Bhaktivedanta Swami then explains, the unsuccessful yogis are divided into two classes: one is fallen after very little progress, and one is fallen after long practice of yoga. The yogi who falls after a short period of practice goes to the higher planets, where pious living entities are allowed to enter. After prolonged life there, one is sent back again to this planet, to take birth in the family of a righteous brahmana vaishnava (Hindu Theists) or of aristocratic merchants.
The real purpose of yoga practice is to achieve the highest perfection of God consciousness, as explained in the last verse of this chapter. But those who do not persevere to such an extent and who fail because of material allurements are allowed, by the grace of the Lord, to make full utilization of their material propensities. And after that, they are given opportunities to live prosperous lives in righteous or aristocratic families. Those who are born in such families may take advantage of the facilities and try to elevate themselves to full God consciousness.
