We have already encountered jnana yoga in the form of the philosophies or systems of thought in Hinduism. Jnana yoga is the path of knowledge and the cultivation of the mind as shown in the Upanishads and the analysis of Shankara (Advaita Vedanta). Through knowledge and insight, one can distinguish between the eternal Self and the temporary one. Once this is achieved, then there is nothing that separates the Self (the atman) from Brahman.
The Bhagavad-Gita suggests that one who truly knows that there is not separation of the divine from the ordinary is set free from the effects of karma (13:27-28):
The one who sees the imperishable Supreme Lord dwelling equally within all perishable beings truly sees.
Seeing the same Lord existing in every being, one does not injure the other self and thereupon attains the Supreme goal.
In contrast to raja yoga, one attains a knowledge of ultimate reality by disciplined intellectual analysis. This type of knowledge may also a basis for karma yoga. Krishna suggests that Arjuna misunderstands the situation when he speaks of killing his own relatives in battle. The true nature of reality is that one cannot destroy the atman because it is eternal and transcendent.
There was never a time when I, you, or these kings did not exist; nor shall we ever cease to exist in the future. (2.12)
The one who thinks that Atma is a slayer, and the one who thinks that Atma is slain, both are ignorant, because Atma neither slays nor is slain. (2.19)
The Atman is neither born nor does it die at any time, nor having been it will cease to exist again. It is unborn, eternal, permanent, and primeval. The Atma is not destroyed when the body is destroyed. (2.20)
In short, jnana yoga breaks down the illusion that the atman is separate from Brahman. Consequently, through knowledge of the truth, one experiences a freedom both to act as well as a freedom from bondage to karma which assumes that we are not part of unchanging reality of Brahman.