It's true that Christians need more than sermons on "You must be born again" and "For God so loved the world", but if they lose the wonder and thrill of the gospel, they have serious spiritual problems. Christians need the gospel as well as unbelievers. Whether we have been saved for two weeks or twenty years, we all need to regularly hear the message of the cross and the grace and love of God in and through the Lord Jesus Christ. That's whey there's nothing more thrilling to a believer than to hear the gospel preached in the power of the Holy Spirit.