The pair have developed a close friendship in recent years and Smith is often referred to as Bieber's pastor.
In an interview with the Christian Post Smith said: "I feel like I have learned more from Justin Bieber than he could ever have learned from me.
"I have been allowed to love him and I feel like we are family. We talk almost every day. And I've learned that what does it profit a man to gain the whole world but in the process lose his soul?
"That all of the trappings that our culture tells us you pursue, leaves us as lifeless as you could possibly imagine.
"What really matters in life, even when you have hundreds of millions and are one of the most famous people in the world, is relationship with God and with each other, authentic relationship."
Bieber often attends services led by the pastor at his City Church in Seattle.
It was previously revealed that the Canadian super star texts his pastor "almost daily" and it's not "just me sending him Bible verses anymore", Pastor Smith said.
"He'll send them to me, along with encouraging thoughts or an encouraging emoticon. I'm committed to helping him and protecting him, but it's fair to say we're there for each other," he added.