Watch The Mission if you haven't, the soundtrack is very good
The same is true for the earlier Robert Bolt film, too: A Man for All Seasons.
The thing that stood out for me in The Mission was its dramatic depiction of the power of repentance (i.e. a genuine change of heart) which we saw when Mendoza (de Niro) finally put down his burden at the intervention of the very people he'd persecuted.
In A Man for all Seasons it would have to be the Thomas More's famous replies following Roper's “So, now you give the Devil the benefit of law!”
https://www.goodreads.com/quotes/7515521-william-roper-so-no...
Funny, though, we still think goodness can be manufactured by the passing of laws instead of by changes of hearts.