In The Crucible, how does Arthur Miller explore that passionately holding onto a belief can both sustain and destroy?

The affairs between Abigail and John is an interesting one
because both characters demonstrate the destructive and creative force behind
conviction.  Abigail's coveting of John as well as her desire to control others proves
how conviction can be dangerous.  She is relentless in her pursuit of the self-
interested notion of the good.  She demonstrates how convictions can be destructive if
they are not aimed at a social, collective, or redemptive vision.  For whatever reason,
Abigail's convictions are driven by her desire to feed her own ends.  Her "mischievous
enjoyment in wielding power of other people's lives" is where her conviction lies.  On
the other hand, John Proctor has to emerge to embracing a sense of conviction that is to
counter Abigail's destruction.  When Proctor cries that his "name" is the most important
element, it is Miller's reminder that while there is a great capacity for evil in the
world, there is an equal propensity for good, for redemption in the convictions of
others who seek to challenge those convictions that destroy.  In this standoff between
Abigail's evil and John's emergence into good, Miller demonstrates the nature of
conviction.  He also pits both his characters and readers to see that there is a choice
to be made as to which type of conviction to embrace.  While the conviction of
destructive self interest is easy to accept, it takes a great deal of courage to embrace
that which is socially redeeming.  Passion is involved in both.  Miller forces the
reader to make conscious choices as to how this zeal is to be
channeled.