The following article by R. Albert Mohler is the best commentary I have read on the ministry and theology of Joel Osteen . . .
In her message, Victoria Osteen tells their massive congregation to realize that their devotion to God is not really about God, but about themselves. “I just want to encourage every one of us to realize when we obey God, we’re not doing it for God–I mean, that’s one way to look at it–we’re doing it for ourselves, because God takes pleasure when we are happy. . . . That’s the thing that gives Him the greatest joy. . . .”
She continued: “So, I want you to know this morning — Just do good for your own self. Do good because God wants you to be happy. . . . When you come to church, when you worship him, you’re not doing it for God really. You’re doing it for yourself, because that’s what makes God happy. Amen?”
Read the entire insightful article, "The Osteen Predicament — Mere Happiness Cannot Bear the Weight of the Gospel," by Dr. Mohler here.