The prison, the impression of limitation is ignorance:
Ignorance of our true Self, our true nature. Ignorance of truth.
Ignorance of truth is the belief that what I truly am is a person, a man/woman, a body/mind; the belief that consciousness is personal and limited to a mortal body mind. The belief in separation and duality. The belief in separate realities, separate consciousnesses. The belief that I, consciousness, exist in time and space.
Truth lovers investigate that set of beliefs and come to the revelation: The revelation that the reality is not of an internal self and an external world, body mind. The revelation of wholeness, seamless, causeless peace and happiness.
It is the investigation of ignorance (identification with form) that leads to the rare revelation of truth. The revelation is that there is no division, no separation to the reality of consciousness and that consciousness is wholeness, universal and impersonal. The revelation that there is one reality, one truth … the reality of universal consciousness. That I am!
Tat Twam Asi.