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.
According to mainstream Christian theology, after death but before the Second Coming, the saved live with God in an intermediate state, but after the Second Coming, experience the physical resurrection of the dead and the physical recreation of a New Earth. The Catechism of the Catholic Church states, "By death the soul is separated from the body, but in the resurrection God will give incorruptible life to our body, transformed by reunion with our soul. Just as Christ is risen and lives for ever, so all of us will rise at the last day." N.T. Wright argues that "God's plan is not to abandon this world... Rather, he intends to remake it. And when he does, he will raise all people to new bodily life to live in it. That is the promise of the Christian gospel."
In the Synoptic Gospels and the Pauline Letters, eternal life is generally regarded as a future experience, but the Gospel of John differs from them in its emphasis on eternal life as a "present possession". Raymond E. Brown points out that in the synoptic gospels eternal life is something received at the final judgment, or a future age (Mark 10:30, Matthew 18:8-9) but the Gospel of John positions eternal life as a present possibility, as in John 5:24.
Thus, unlike the synoptics, in the Gospel of John eternal life is not only futuristic, but also pertains to the present. In John, those who accept Christ can possess life "here and now" as well as in eternity, for they have "passed from death to life", as in John 5:24: "He who hears my word, and believes him that sent me, has eternal life, and comes not into judgment, but has passed out of death into life." In John, the purpose for the incarnation, death, resurrection and glorification of The Word was to provide eternal life to humanity.
In the New Testament
Scholars such as John H. Leith assert that eternal life is never described in detail in the New Testament, although assurances are provided that the faithful will receive it. Other scholars such as D. A. Carson suggest that eternal life is explicitly defined in John 17:3, where Jesus says in his High Priestly Prayer, "Now this is eternal life: that they may know you, the only true God, and Jesus Christ, whom you have sent." Carson says of this verse that "Eternal life turns on nothing more and nothing less than knowledge of the true God" and that it is "not so much everlasting life as personal knowledge of the Everlasting One." The Eerdmans Dictionary of the Bible on the other hand, contends that "the nature of eternal life is only sketched in its essential elements in the New Testament".
John W. Ritenbaugh says that eternal life is knowing God, and that Jesus implies an intimate relationship with God that matures over time.
While the Synoptic Gospels are seen as focusing on the proclamation of the Kingdom of God, some scholars see eternal life as the central theme of Jesus' preaching in the Gospel of John, where receiving eternal life is seen to be synonymous with entering the Kingdom. In Christian teachings, eternal life is not an inherent part of human existence, and is a unique gift from God, based on the model of the Resurrection of Jesus, viewed as a unique event through which death was conquered "once for all", permitting Christians to experience eternal life. This eternal life is provided to believers, generally assumed to be at the resurrection of the dead.