Sometimes Jesus refers to this life which he came to give simply as "life", and he presents being born of God as a necessary condition if man is to attain the end for which God has created him: "Unless one is born anew, he cannot see the kingdom of God" (Jn 3:3). To give this life is the real object of Jesus' mission: he is the one who "comes down from heaven, and gives life to the world" (Jn 6:33). Thus can he truly say: "He who follows me ... will have the light of life" (Jn 8:12).
At other times, Jesus speaks of "eternal life". Here the adjective does more than merely evoke a perspective which is beyond time. The life which Jesus promises and gives is "eternal" because it is a full participation in the life of the "Eternal One". Whoever believes in Jesus and enters into communion with him has eternal life (cf. Jn 3:15; 6:40) because he hears from Jesus the only words which reveal and communicate to his existence the fullness of life. These are the "words of eternal life" which Peter acknowledges in his confession of faith: "Lord, to whom shall we go? You have the words of eternal life; and we have believed, and have come to know, that you are the Holy One of God" (Jn 6:68-69). Jesus himself, addressing the Father in the great priestly prayer, declares what eternal life consists in: "This is eternal life, that they may know you the only true God, and Jesus Christ whom you have sent" (Jn 17:3). To know God and his Son is to accept the mystery of the loving communion of the Father, the Son and the Holy Spirit into one's own life, which even now is open to eternal life because it shares in the life of God.
38. Eternal life is therefore the life of God himself and at the same time the life of the children of God. As they ponder this unexpected and inexpressible truth which comes to us from God in Christ, believers cannot fail to be filled with ever new wonder and unbounded gratitude. They can say in the words of the Apostle John: "See what love the Father has given us, that we should be called children of God; and so we are. ... Beloved, we are God's children now; it does not yet appear what we shall be, but we know that when he appears we shall be like him, for we shall see him as he is" (1 Jn 3:1-2).
Here the Christian truth about life becomes most sublime. The dignity of this life is linked not only to its beginning, to the fact that it comes from God, but also to its final end, to its destiny of fellowship with God in knowledge and love of him. In the light of this truth Saint Irenaeus qualifies and completes his praise of man: "the glory of God" is indeed, "man, living man", but "the life of man consists in the vision of God".27
Immediate consequences arise from this for human life in its earthly state, in which, for that matter, eternal life already springs forth and begins to grow. Although man instinctively loves life because it is a good, this love will find further inspiration and strength, and new breadth and depth, in the divine dimensions of this good. Similarly, the love which every human being has for life cannot be reduced simply to a desire to have sufficient space for self-expression and for entering into relationships with others; rather, it devel- ops in a joyous awareness that life can become the "place" where God manifests himself, where we meet him and enter into communion with him. The life which Jesus gives in no way lessens the value of our existence in time; it takes it and directs it to its final destiny: "I am the resurrection and the life ... whoever lives and believes in me shall never die" (Jn 11:25-26).