The Buddhist awareness of the of the pervasiveness of essential life in all things, both sentient and sentient beings, leads to the awareness of eternity of life. The greatest obstacle in a way of accepting the eternity of life is the ineveitability of death. But is one accepts the transition from latent state to a manifest state- that is from insentient to sentient- one must also accepts the transition from sentient to inmsentient. Death is the point at which life returns to latent state(ku).I had explain this one in my previous post on " How Buddhism looks in to the universe.
The substance harboring and supporting life in the living organism may become faulty or fail in one way or another.If the the breakdown is not serious, the living organism becomes ill and recovers. Upon death, the substance that formerly supported life decompose aand lose the ability to shelter life., which departs to blend with essential life, not that like other religions taught born into some myhical heaven or paradise.. This cycle continous eternally and therefore "LIFE" itself is ETERNAL. BIrth and Death phenomena occuring everywhere , are only varying modes of ESSENTIAL LIFE. The life of individual cannot be said to exist any specific place after death. It is ,however, part of universal essential life and is awaiting remanifestion in the world of actuality. Nicheren writes : " When the time is right and the condition is perfect LIFE will Exist ".This is the teaching of Buddhism.(Please see further my post on the ETERNITY OF LIFE)