Piece in good works about divine persons (7)
I believe the answer is:
oddment
'piece' is the definition.
(I know that oddment is a type of piece)
'good works about divine persons' is the wordplay.
'good works' becomes 'ot' (I can't justify this - if you can you should believe this answer much more).
'about' indicates putting letters inside.
'divine' becomes 'dd' (divine can mean theologian eg Doctor of Divinity).
'persons' becomes 'men' (man is a kind of person).
'dd'+'men'='ddmen'
'ot' going around 'ddmen' is 'ODDMENT'.
'in' is the link.
Can you help me to learn more?
(Other definitions for oddment that I've seen before include "An isolated article, something left over" , "Just a bit left" , "Left over item" , "spare part?" , "Curiosity, peculiarity" .)