Missler says it well here in his discussion on Islam and Christianity:

Islam is making its way in the West, but it would have far less success without dead Christianity. Dead Christianity is a vaccine that inoculates people against the real thing. True Christianity is full of life and health through the Spirit of God. Dead Christianity has few answers, and looks no different than any other religion on earth. Christ-centered Christianity is full of holy power that frees people and heals lives. The Christians of Iran have found what too many Western churches have lost - Jesus Christ. If we get him back in our churches, in our homes and our lives, we'll be leading the Muslims to him, rather than the other way around.