If “eternal life” doesn’t mean “life after death,” what does it mean? Later in John’s Gospel, Jesus reduces the phrase simply to “life,” or “life to the full.” near the end of John’s account, Jesus makes a particularly fascinating statement in a prayer, and it is as close as we get to a definition: “This is eternal life: that they may know you, the only true God, and Jesus Christ, whom [God has] sent” (John 17:3). So here, “eternal life” means knowing, and knowing means an interactive relationship. In other words, “This is eternal life, to have an interactive relationship with the only true God and with Jesus Christ, his messenger.” Interestingly, that’s what a kingdom is too: an interactive relationship one has with a king, the king’s other subjects, and so on.

The Greek phrase John uses for “eternal life” literally means “life of the ages,” as opposed, I think we could say, to “life as people are living it these days.” So John’s related phrases – eternal life, life to the full, and simply life – give us a unique angle on what Jesus meant by “kingdom of God” : a life that is radically different from the way people are living these days, a life that is full and overflowing, a higher life that is centered in an interactive relationship with God and with Jesus. Let’s render it simply “an extraordinary life to the full centered in a relationship with God.”

– Brian McLaren, The Secret Message of Jesus