Advaita Vedanta is one of the most ancient schools of Hindu Vedantic philosophy, leading to self-realization.
The Sanskrit term “advaita” means “non-duality”.
Also called the direct or the pathless path, Advaita reveals that the true Self is identical to Brahman, the Absolute Reality.
Advaita Vedanta traces its roots to the oldest Upanishads.

I am other than name, form and action.
My nature is ever free!
I am Self, the supreme unconditioned Brahman.
I am pure Awareness, always non-dual.

Adi Shankara, Upadesasahasri 11.7

अद्वैत वेदान्त

“The wise man should, at all times, meditate attentively
upon his own Self which, though unseen, is yet the only reality
and though manifest as the external universe,
is yet of a nature of subjective consciousness.”
Sri Adi Shankara

I am itself is God. The seeking itself is God.
In seeking you discover that you are neither the body nor mind,
and the love of the self in you is for the self in all. The two are one.
The consciousness in you and the consciousness in me,
apparently two, really one, seek unity and that is love.”
Sri Nisargadatta Maharaj

“Abiding in one’s natural consciousness, I am, is samadhi.
Being freed from the adjunct-mixed awareness —  ‘I am so-and-so’,
‘I am the body’, ‘I am a man’, ‘I am this or that’ and so on — ,
firmly abide in this boundless state of real samadhi.”
Sri Ramana Maharshi