From other
dialogs here, I thought it best to start a thread on a parallel concept between Buddhism's concept of the deathless verses Christianity's concept of eternal life' and from the perspective of a mystic, not from a devout follower of either religion.
In my experience of traveling out of body, through space and time I found, while the body is impermanent and will eventually die; nonetheless, that which can travel out of body, through space and time, lives on, and never dies. This, I believe is what was referred to in the suttas as the deathless (amatta), and I also believe it is precisely the 'eternal life' (aiōnios αἰώνιος eternal, zōē ζωὴ life) that is referred to in the Gospels.
I have spent some time investigating the concept of the "deathless" as it appears in the suttas. The deathless in Pali is 'amatta.' The Buddha, upon his enlightenment said he had arrived to the deathless. Now, the question is how did he know he had arrived at the deathless?
I took an Anthropologist's approach to this question, and asked how did the people at the time of Siddhartha Gautama consider death? Death in most pre-Western thought oriented cultures considered death and dreaming essentially the same thing. This means they believed when one dreamed one was in contact with the after-life. If the above was true then when Siddhartha Gautama had arrived at lucid dreaming throughout the night, as I do, then he believed that he had arrived at the deathless (amatta).
Now the concept of the deathless (amatta) has some significance to Christianity's use of the concept of "everlasting (eternal) life." I believe both concepts are parallel, but it is difficult to argue it within a purely intellectual and/or Abrahamic scriptural context. But, I believe Jesus the Nazarite was a contemplative who had become a mystic, in the same way Siddhartha Gautama was, and they had arrived at unbroken consciousness, as I have arrived at it in the same way, and they interpreted it within their culture and language.
In Christianity, the term eternal life traditionally refers to continued life after death, as outlined in Christian eschatology. The Apostles' Creed testifies: "I believe... the resurrection of the body, and life everlasting." In this view, eternal life commences after the second coming of Jesus and the resurrection of the dead, although in the New Testament's Johannine literature there are references to eternal life commencing in the earthly life of the believer, possibly indicating an inaugurated eschatology.
16 For God so loved the world that he gave his chosen Son, that whoever believes (πιστεύων) in him shall not perish but have eternal life (ζωὴν αἰώνιον).
I do not believe that John 3:16 is just about believing some belief system, but accepting the Nazarite lifestyle and living it. And, the Nazarite lifestyle is a dedicated contemplative lifestyle.
So, this is an attempt to answer your questions by taking them up a notch. An arahat is one who has become lucid 24-7 through leading a dedicated contemplative lifestyle. Thus, they can come and go from the material plane at will, nonetheless, all physical bodies decay and die. The physical body is just a temporary vehicle, which the arahat has no attachment for. It is just a vehicle for him/her to help a few of the suffering beings on this plane to move beyond this plane to higher planes of existence.
The arahat has no identity; therefore, they do not exist in the sense that others think in terms of existence.
Sources for the Deathless (Amata):
Deathless, door to (Amatassa dvara) DN: 14.3.7; 18.27; n 535
MN: 26.12; 26.18; 26.20f; 52.15; 64.9ff; 106.13; n. 1023
SN: 216; 232-233; 268; 290; 432 n. 368; 461-62 n. 510; 464-65 n 522; 1528; 1549-50; 1658; 1660; 1690; 1699
Ariyapariyesana Sutta (MN: 26.12; 26.18; 26.20f)
The Noble Search
“And, what is the noble search? Here someone being subject to birth seeks the unborn supreme security from bondage, Nibbana; being subject to aging, having understood the danger in what is subject to ageing, he seeks the unageing supreme security from bondage, Nibbana; being subject to sickness, having understood the danger in what is subject to sickness, he seeks the unailing supreme security from bondage, Nibbana; being subject to death, having understood the danger in what is subject to death, he seeks the deathless supreme security from bondage, Nibbana; being subject to sorrow, having understood the danger in being subject to sorrow, he seeks the sorrowless supreme security from bondage, Nibbana; being subject to defilements (corruption), having understood the danger in what is subject to defilement, he seeks the undefiled supreme security from bondage, Nibbana. This is the noble search.” Having “…attained the undefiled supreme security from bondage, Nibbana,” the Buddha said, “the knowledge and vision arose in me: ‘My deliverance is unshakeable; this is my last birth; now there is no renewal of being.’”