(Note: I posted a bunch of quotes as a sort-of precursor to this blog on Facebook and wanted to include it here as it fits with the purpose of this blog.)
One way to describe this problem is to say that when these people “receive Christ,” they do not receive him as supremely valuable. They receive him simply as sin-forgiver (because they love being guilt-free), and as rescuer-from-hell (because they love being pain-free), and as healer (because they love being disease-free), and as protector (because they love being safe), and as prosperity-giver (because they love being wealthy), and as creator (because they want a personal universe), and as Lord of history (because they want order and purpose). But they don’t receive him as supremely and personally valuable for who he is. They don’t receive him the way Paul did when he spoke of “the surpassing worth of knowing Christ Jesus my Lord.” They don’t receive him as he really is—more glorious, more beautiful, more wonderful, more satisfying, than everything else in the universe. They don’t prize him or treasure him or cherish him or delight in him.
Such a “receiving” of Christ is the kind of receiving an unregenerate, “natural” person can do. This is a “receiving” of Christ that requires no change in human nature. You don’t have to be born again to love being guilt-free and pain-free and disease-free and safe and wealthy. All natural men without any spiritual life love these things. But to embrace Jesus as your supreme treasure requires a new nature. No one does this naturally. You must be born again (John 3:3). You must be a new creation in Christ (2 Cor. 5:17; Gal. 6:15). You must be made spiritually alive (Eph. 2:1–4). “No one can say 'Jesus is Lord’ [and mean it!] except in the Holy Spirit” (1 Cor. 12:3).
John Piper, "Think", pp. 71-72