How do the characteristics of Rev. John Hale and Rev. Samuel Parris differ in Act III specifically?

Act III reveals some basic differences in both Reverends. 
Hale is shown to be one who begins to questions what is happening in Salem.  When he
explains to Danforth how he possesses ambivalence about signing Rebecca Nurse's death
sentence as well as how he begins to openly object to how Abigail and the girls are
manipulating their ability to lauch accusations, there is a revelation of how Hale is
losing faith in the Salem justice system.  This is in fairly stark opposition to
Parris.  As Hale's doubt increases, Parris' zeal also increases.  He is of the mindset
that any questioning of the process results in a questioning of his own position,
helping to explain his own sense of certainty in the system.  At the same time, Parris
begins to see that Proctor's motivations are divergent, and in the midst of his moral
and ethical anguish, there lies an opportunity to silence one of Parris' most vociferous
critics once and for all.  Parris recognizes this and starts to increase the poison in
the trials and in the Act, itself, in order to consolidate his own power and strengthen
his own position.  Whereas Parris sees a self- serving opportunity present, Hale sees
hypocrisy evident, and this helps to explain why both Reverends proceed in different
directions and trajectories in Act III.