The differences of a person in knowledge and a person who is not can be calculated,  as well as what we mean by knowledge,  the Vedic description tells of knowledge of an impersonal all pervasiveness form of Divinity,  His localised and more personal feature that gives everything form and substance and His confidential original forms , those that exhibit His Godhead originating in Lord Krishna.  That person in knowledge of some or all these features would have acquired Jnana , or buddhi yoga , the yoga of intelligence .
This knowledge is brought about in various ways and generally through many lives . Sacrifices of many kinds and following honest duties and morality ethics kindness and compassion brings knowledge very close , the honest attract truth and can easily accept truth .
It is recommended in the Vedas , that a person who is inhabited by a ghost , needs to engage himself in purificatory processes of different kinds , and after acting accordingly,  like an ordinary man should do , he will regain knowledge of who he is , ie . He is a man, not a ghost .When one is inhabited by ghostly elements,  the ghosts affect thinking and actions and subdue the good sense of a person.
By repeatedly telling the man he is not a ghost won’t do ,the ghost will overpower him . He must engage in purificatory actions to revive his true position and cast out the ghost.
Karma yoga, as in Niskama karma yoga, leads to knowledge of God and knowledge of ones true self as an associate of God . The process of jnana alone is not suitable for 99.9 % of people, but  by Niskama karma yoga, one automatically aquires knowledge by working correctly under the directions of the spiritual intelligentsia .The candidate can realise the original source of  all energies within and outside the body . Also, how best they can be  employed for the benefit of an individual and everyone else will be realised . An offering of energy  back to the energetic source is the prescribed methods  .By Niskama karma yoga ,  one soon realises the futility of temporary action within matter , and a strong realisation comes about , dualism and consciousness and  its origins  are gradually realised in full . Jnana or buddhi yoga are the result of pure actions. Automatically reviving pure knowledge of a person who is artificially trying to enjoy matter.  The inner consciousness is not made of matter , so matter will never satisfy consciousness.  The ghost like illusion of being something one is not is cleared up by Niskama karma yoga leading to pure Jnana .  Then, pure Bhakti, the yoga of pure devotional service can be understood and practised to perfection,  its only this which reveals one’s spiritual form in relation to God , that is carried out under the directions of a Diksa Guru and many Siksa Gurus including Sastra sanga.
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