Bhagavan Shri Krishna said: Because you are not envious I shall now explain to you the greatest of all secrets. I shall explain this knowledge and it’s realization, knowing which you shall become free from all inauspiciousness.
Bhagavad Gita - Chapter 9 - Raja Guhya Yoga - The Yoga of the Greatest Secret
This is the greatest of all knowledge (raja-vidya) and the greatest of all secrets (raja-guhya). It is most purifying and most excellent. This path of dharma is directly perceived; it is simple to practice and imperishable.
O vanquisher of the enemy, those that lack faith in this path of dharma can never attain Me and are forced to be reborn in the continuous cycle of birth and death.
I pervade the entire cosmos through My unmanifest form. All living beings are supported by Me, but I am not supported by them.
Yet everything that is created does not rest in Me. Behold My divine powers! Although I am the origin of all living beings and I maintain them, I am not influenced by them nor by My material nature.
Try to understand that just as the mighty wind rests within the vast expanse of the sky, similarly all beings rest within Me.
O son of Kunti, at the end of a day of Brahma, all living beings enter into Me. I manifest them again at the beginning of a new creation.
Because I control material nature, I continuously manifest the living beings that are helplessly manipulated by their natures.
O Dhananjaya, such actions cannot bind Me. I am detached and indifferent to these activities.
Under My command, material nature produces the universe with all its moving and non-moving beings. O son of Kunti, because of this the universe continually manifests.