Advaita Vedanta

Advaita Vedanta says that the soul is not different from Brahman.

The most famous Hindu philosopher who taught us about Advaita Vedanta was Adi Shankara.

Adi Shankara Advaita Vedanta Theory:

According to Advaita Vedanta, liberation can be achieved while living and is called Jivanmukti. The Atman-knowledge, that is the knowledge of true Self and its relationship to Brahman is central to this liberation in Advaita thought:

Brahamsutra – Everything is connected.
This connected whole is called consciousness or Brahman
This consciousness (Brahman) is also our personal consciousness (Atman)
Our personal consciousness is what we are.
there is no separate self, there is no separate self to suffer, this realization is the end to of suffering
Brahman is the fundamental reality underlying all objects and experiences.
Brahman is explained as pure existence, pure consciousness and pure bliss.
Advaita: non-dualism, only one substance exists in the universe, Brahman
Brahman: Brahman is impersonal, beyond all qualities, it’s nothing and everything.
Jiva is an illusory separate self. Atman is the true self or universal consciousness.
Jiva is to atman like the reflection in the mirror is to the person who causes the reflection.
Atman is said to be like space and the jiva is like space in a jar.
The uniqueness of jiva in human form: Humans have self-consciousness, the capacity to reason, the ability to make moral and immoral choices, have greater freedom to make these choices regarding spiritual progress, however, there is greater opportunity to act immorally and backslide.
Distractions, delusions, ignorance, selfishness and base impulses and desires as Karma to jiva which obscures atman, prevents humans from realizing atman is Brahma.
Non-duality path for those who see Brahman and atman as the same, The atman that is trapped by the jiva is then reincarnated in different forms in samsara the cycle of rebirth.