Poetry included in clever sermon (5)
I believe the answer is:
verse
'poetry' is the definition.
(lines written in verse)
'included in clever sermon' is the wordplay.
'included in' indicates a hidden word.
'VERSE' is hidden within 'clever sermon'.
(Other definitions for verse that I've seen before include "Poetry, a poem" , "Poetry - subdivision of the Bible" , "Poems" , "Part of hymn" , "Piece of poetry" .)