It is true that the great principle of repentance is always available, but for the wicked and rebellious there are serious reservations to this statement.
For instance, sin is intensely habit-forming and sometimes moves men to the tragic point of no return. Without repentance there can be no forgiveness, and without forgiveness all the blessings of eternity hang in jeopardy.
As the transgressor moves deeper and deeper in his sin, and the error is entrenched more deeply and the will to change is weakened, it becomes increasingly near-hopeless, and he skids down and down until either he does not want to climb back or he has lost the power to do so.
(Spencer W. Kimball, Miracle of Forgiveness, p. 117)