The volcano is quiet and silent for years. No fires and lava pour forth from its crater. Meanwhile, people venture up its slopes, and lay out their gardens, and build their villas, and plant their vineyards. And flowers bloom, and fruits hang in purple clusters, and beauty covers the once fire-swept, lava-furrowed mountain slopes. But has the volcano really been tamed? Have its fires been put out? Is all permanently peaceful in the volcano's heart?
Just so is the heart of a man, who has merely trained himself into good moral and ethical habits. What the best mere self-culture can do for a life — is no more than the planting of flowers and vineyards on the volcano's sides — while all its fires still burn within, ready to break forth again any day in all their old fury! Good manners are not saving religion. The heart must be changed. The heart of stone, must be made a heart of flesh. The heart that hates God, and holiness and purity — must become a heart that loves God, His holy ways, and His holy Word.
"I will give you a new heart and put a new spirit within you; and I will remove the heart of stone from your flesh and give you a heart of flesh. I will put My Spirit within you and cause you to walk in My statutes, and you will be careful to observe My ordinances." Ezekiel 36:26-27