It is wisperd in the ear of dying to guide them to the ultimate goal of trasnceding karma and physical existence or if you fail assistance is in trying to get a favorable reincrnation. From what I read the real goal of the yogic praces is to stay aware and alert as you pass beyond death and be able to stay in a transcendent state. Lose awareness or are insufficiently prepared and you sink back into the cycle of birth and rebirth.

I always took it as metaphor. Back in the 70s I puzzled over it for a while until I realized it was more of a psychology of the living, or that was my conclusion.

If you want something more intyeresting than the bible read the Evans-Wentz traslation with its commentray. Interesting but as always take his commentray and conclusions with a grain of salt.

An onlibe traslation. A very detailed theology of consioness.

It so happens a Tbetan monk lives in my biulding. Whiel American he wears traditional clothes and has a Tibetan name. He travels to Nepal. Ne teacjes peoplein the building meditaion.

The Bardo Thodol (Tibetan: བར་དོ་ཐོས་གྲོལ, Wylie: bar do thos grol, "Liberation Through Hearing During the Intermediate State"), commonly known in the West as The Tibetan Book of the Dead, is a text from a larger corpus of teachings, the Profound Dharma of Self-Liberation through the Intention of the Peaceful and Wrathful Ones,[1][note 1] revealed by Karma Lingpa (1326–1386). It is the best-known work of Nyingma literature.[3]
The Tibetan text describes, and is intended to guide one through, the experiences that the consciousness has after death, in the bardo, the interval between death and the next rebirth. The text also includes chapters on the signs of death and rituals to undertake when death is closing in or has taken place.

Three bardos[edit]
Main article: Bardo
The Bardo Thodol differentiates the intermediate state between lives into three bardos:
The chikhai bardo or "bardo of the moment of death", which features the experience of the "clear light of reality", or at least the nearest approximation of which one is spiritually capable;
The chonyid bardo or "bardo of the experiencing of reality", which features the experience of visions of various Buddha forms, or the nearest approximations of which one is capable;
The sidpa bardo or "bardo of rebirth", which features karmically impelled hallucinations which eventually result in rebirth, typically yab-yum imagery of men and women passionately entwined.
The Liberation Through Hearing During the Intermediate State also mentions three other bardos:[note 3]
"Life", or ordinary waking consciousness;
"Dhyana" (meditation);
"Dream", the dream state during normal sleep.
Together these "six bardos" form a classification of states of consciousness into six broad types. Any state of consciousness can form a type of "intermediate state", intermediate between other states of consciousness. Indeed, one can consider any momentary state of consciousness a bardo, since it lies between our past and future existences; it provides us with the opportunity to experience reality, which is always present but obscured by the projections and confusions that are due to our previous unskillful actions.