From John Piper’s sermon on Sunday:
Millions of nominal Christians have never experienced a fundamental alteration of that foundation of happiness. Instead they have absorbed the notion that becoming Christian means turning to Jesus get what you always wanted before you were born again. So, if you wanted wealth, you stop depending on yourself for it, and by prayer and faith and obedience you depend on Jesus for wealth. If you wanted to be healthy, you turn from mere human cures to Jesus as the source of your health. If wanted to escape the pain of hell, you turn to Jesus for the escape. If you wanted to have a happy marriage, you come to Jesus for help. If you wanted peace of conscience and freedom from guilt feelings, you turn to Jesus for these things.
In other words, to become a Christian, in this way of seeing things, is to have all the same desires you had as an unregenerate person—only you get them from a new source, Jesus. And he feels so loving when you do. But there’s no change at the bottom of your heart and your cravings. No change in what makes you happy. There’s no change in the decisive foundation of your joy. You just shop at a new store. The dinner is still the same; you just have a new butler. The bags in the hotel room are still the same; you just have a new bellhop.
That’s not what the new birth is. It’s not having all the same desires that you had as an unregenerate person, and just getting them from a new source. The new birth changes the bottom, the root, the foundation of what makes us happy. Self at the bottom is replaced by Jesus. God, himself.
The full sermon is here.