Go on a yarn with me for a moment. Read these key scriptures, and then I will explain at the end. The key here is The Word of God.
As God spoke through Isaiah the prophet...
"The voice of him that crieth in the wilderness, Prepare ye the way of the LORD, make straight in the desert a highway for our God.
Every valley shall be exalted, and every mountain and hill shall be made low: and the crooked shall be made straight, and the rough places plain:
And the glory of the LORD shall be revealed, and all flesh shall see it together: for the mouth of the LORD hath spoken it.
The voice said, Cry. And he said, What shall I cry? All flesh is grass, and all the goodliness thereof is as the flower of the field:
The grass withereth, the flower fadeth: because the spirit of the LORD bloweth upon it: surely the people is grass.
The grass withereth, the flower fadeth: but the word of our God shall stand for ever."
And as the Apostle Peter writes...
"And if ye call on the Father, who without respect of persons judgeth according to every man's work, pass the time of your sojourning here in fear: Forasmuch as ye know that ye were not redeemed with corruptible things, as silver and gold, from your vain conversation received by tradition from your fathers; But with the precious blood of Christ, as of a lamb without blemish and without spot: Who verily was foreordained before the foundation of the world, but was manifest in these last times for you, Who by him do believe in God, that raised him up from the dead, and gave him glory; that your faith and hope might be in God.
Seeing ye have purified your souls in obeying the truth through the Spirit unto unfeigned love of the brethren, see that ye love one another with a pure heart fervently: Being born again, not of corruptible seed, but of incorruptible, by the word of God, which liveth and abideth for ever. For all flesh is as grass, and all the glory of man as the flower of grass. The grass withereth, and the flower thereof falleth away: But the word of the Lord endureth for ever. And this is the word which by the gospel is preached unto you."
The Apostle John writes...
"In the beginning was the Word, and the Word was with God, and the Word was God.The same was in the beginning with God. All things were made by him; and without him was not any thing made that was made.In him was life; and the life was the light of men. And the light shineth in darkness; and the darkness comprehended it not."
The Apostle James writes...
"Every good gift and every perfect gift is from above, and cometh down from the Father of lights, with whom is no variableness, neither shadow of turning. Of his own will begat he us with the word of truth, that we should be a kind of firstfruits of his creatures."
So what does all of this mean?
Eternal Life is The Truth, and the entire Christian discipline is abiding in The Truth, because everything else is destined to burn eternally in the fire that is reserved for the devil and his angels.
What makes life for you? What is your identity? Is that who you really are, or is it an illusion? In the end, everything will be revealed for what it truly is, in a way that we, as creatures who were made to not see things as they truly are can fathom.
So what is eternal life?
"And this is life eternal, that they might know thee the only true God, and Jesus Christ, whom thou hast sent."
Jesus Christ is The Word of God, and as you can see from that quotation from John, everything was created by and through the word of God. Jesus Christ is here among us. This is the mystery of The Word being made flesh if you can understand.
"Hereby know ye the Spirit of God: Every spirit that confesseth that Jesus Christ is come in the flesh is of God."
Salvation is of God The Father, The Son, The Holy Spirit.
Simply put, God Saves. If you abide in death, you will die eternally. If you abide in The Truth you will live eternally.
It's all about God.
Or as John the Baptist said, and really, all Christians should say, "I must become less, so that He becomes more."