Prophet’s manners showing a change of heart (5)
I believe the answer is:
moses
'prophet's' is the definition.
(I know that Moses is a prophets)
I can't explain the rest of the clue.
(Other definitions for moses that I've seen before include "One given tablets" , "Aaron's brother" , "Lawmaker" , "Ancient lawgiver" , "Grandma __, American folk artist, d. 1961" .)