...John normally translates "kingdom of God" into another phrase that is notoriously hard to render in English. Most commonly, John's translation of Jesus' original phrase is rendered "eternal life" in English. Unfortunately, the phrase eternal life is often misinterpreted to mean "life in heaven after you die"--as are kingdom of God and its synonym, kingdom of heaven-- so I think we need to find a better rendering.
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 in these days".
From p.38-39 of the same book.
In a story told by Luke, Jesus has a conversation with a man identified as rich, young, and soem sort of political official (Luke 18:18-25). He asks Jesus how he can experience "eternal life"--again, not to be confused with "life after you die"
I am struck, first off, but a seeming lack of any support for McLaren's redefining of "eternal life". There is only one sort of footnote in any of the paragraphs around the phrases above, and that has to do with the use of the phrase "interactive relationship", which he credits to Dallas Willard.
Here is the definition of the word translated "eternal" in "The KJV New Testament Greek Lexicon" found here
without beginning and end, that which always has been and always will be
without end, never to cease, everlasting
I would also like to point you to this page on the same site, a result of a search I did for the words "eternel" and "life". You can see how the phrase is used not just in John, but in the other Gospels as well.
The problem for me comes in, then, when I try to understand what McLaren thinks John and the others mean by "eternal life". As he puts it here, on p 37...
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.
First, I find it a little puzzling, and amusing, that someone who says that we tend to see things in a mechanistic way in regards to God and miracles, here uses the word "interactive" in regards to our relationship with God (true, he credits Dallas Willard with the concept in the footnotes, but he is using it as well), seeing as that word is pretty closely tied to things computer-ish. And when we talk about interactive in regards to computers, we don't mean that the user treats the computer as some kind of equal, or even cares what the computer 'thinks' or 'feels', but only in how to program or website responds to certain actions--move the mouse over a button and get a drop-down menu, press a couple of keys and save a document, even talk into a microphone and have it recorded on file.
Yes, one could have all kinds of fun deconstructing the phrase "interactive relationship", even to the point of contending that those two words together make an oxymoron. But I digress...
Much depends on what McLaren means by his seeming redefining of "eternal life", especially in regards to the place on p 37 where he contends that the phrase means "life of the ages". Here is more about that...
So John's related phrases...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." (By the way, I don't expect you to be satisfied with this as a full definition of the kingdom of God. I'm not satisfied with it myself. But it's one angle, one dimension, one facet.)
If he means that living as a Christian should make a difference in one's life beyond simply assuring one of life in Heaven after death, all well and good. But then, that's hardly a new message, certainly not a 'secret message', as I've heard it all my life, and doubt I'm all that unique.
I'm pretty sure that McLaren doesn't deny life after death, as I think I've read at least one mention of his fondness for the teaching in "Secret Message...". I'm not sure yet what exactly he means, or why he thinks he's all that new and "secret".