Piece of work for man of patience
I believe the answer is:
job
I believe this clue is a double definition.
'piece of work' is the first definition.
(a job is a task or piece of work)
'man of patience' is the second definition.
(biblical character famous for patience)
'for' is the link.
(Other definitions for job that I've seen before include "Employment" , "Patient figure in the Bible - task" , "Personification of patience" , "Post" , "Assignment" .)