Alma 26

 We read that when Alma was given the charge to deal with those that had committed religious crimes - 

"the spirit of Alma was again troubled; and he went and inquired of the Lord what he should do concerning this matter, for he feared that he should do wrong in the sight of God.

14 And it came to pass that after he had poured out his whole soul to God..."  (Mosiah 26:13–14)

In my mind, one of the reasons Alma was so troubled was that he knew at one time, he too, had been a wicked priest. 

Obviously, it all came down to justice and mercy.  Forgiveness for those who would truly repent.