Sin destroys the will, the faculty by which the mind makes choices and carries them out. The progression runs: sow an act and reap a habit; sow a habit and reap a character; sow a character and reap a destiny. At first a person engages in some forbidden pleasure against his will, out of weakness, curiosity, or carnality. If the practice continues, he sins because he cannot help it, for addiction is setting in. Once the sin is a habit, he regards it as nearly a necessity, and when it becomes a necessity, his destiny is produced. Hebrews 3:12-14 warns of being hardened through the deceitfulness of sin. Sin is seductively misleading, promising pleasure, contentment, and fulfillment that it cannot deliver. Its pleasure is fleeting and never quite enough, and this is why it is addictive. It lures people on toward greater and deeper perversions until it ends in death. All along the way, sin quietly produces hardness of heart. Like a callus that stiffens a joint, it paralyzes right action. The Greek word for hardness, skleruno, means impenetrable, insensitive, blind, or unteachable. A hardened attitude is the product of a habitual state of mind, revealed in inflexible thinking and an insensitive conscience. Eventually it makes repentance impossible, because the will to do right is completely gone.