"We proclaim to you the Eternal Life which was with the Father was revealed to us…so that you also may have koinonia with us; and truly our koinonia is with the Father and His Son" (1Jn.1:2-3).
For John, eternal life was not just a thought about what would happen after he died. Eternal Life was a person! And John's gospel was not about going to heaven when you die. It was about knowing God Himself. "This is eternal life … to know You, the only true God" (Jn.17). "Eternal life" to John was a shorthand way of describing life with God and life from God, beginning here and now.
Using a very rough analogy, a TV does not have any life of its own. It cannot function as it was designed unless it is connected to a power source and receives a constant flow of current. Similarly, we are spiritually dead without God. When we become connected to Him through regeneration, we begin to live from His constant flow of life of the eternal kind into our soul. John understood from his own experience that Eternal Life is by definition, being connected to the Eternal One. Jesus said, "He who drinks of the water that I shall give him will never die." Life comes from God. And that is what it means to be saved from death.
This is why we must never sell the gospel short by presenting it as a plan by which people can go to heaven when they die. Salvation is not a visa stamp on your passport. It is to discover life, as it was meant to be — connected to Eternal LIfe Himself.