Having read this sentence, you may perhaps better understand why I believe a person can affiliate with Jesus in the kingdom-of-God dimension without affiliating with him in the religious kingdom of Christianity. In other words, I believe that Christianity is not the kingdom of God. The ultimate reality is the kingdom of God, and Christianity at its best is here to proclaim and lead people into that kingdom, calling them out of smaller rings, smaller kingdoms. Christianity at its worst, using the definition in this paragraph, can become a sin when it holds people within its ring and won't let them enter the kingdom of God. Jesus diagnosed the religious leaders of his day as doing this very thing.
And another related one:
In the previous chapter, I suggested that Jesus didn't come to start another religion, which would include the Christian religion. I wasn't kidding. I do, in fact, believe that. That the Christian religion formed as it has is not surprising. It was no doubt necessary and in many ways good, and I know God is in it, and I am in it, too. But "the Christian religion" is neither the ultimate goal of Jesus nor the ultimate goal of God, in my view. Rather, the goal of Jesus is the kingdom of God, which is the dream of God, the wish and hope and desire of God for creation-like a parent's hopes and dreams for a beloved child.
And if your are wanting to reference this and wondering the page numbers, sorry. I scanned the quotes in by taking digital photos of the pages, which only caught a fdew of the page numbers, and so you're just gonna have to take my word on it... it's all in there.
And in the book McLaren points to this article by Joshua Masssey, His Ways Are Not Our Ways. Good read. Kind of a postmodern missiology. Go find out what a Muslim follower of Jesus is.