Poet in first half of sermon about writers (7)
I believe the answer is:
spenser
'poet' is the definition.
(16th-century poet Edmund Spenser)
'first half of sermon about writers' is the wordplay.
'first half of' means to take half the letters.
'about' means one lot of letters goes inside another.
'writers' becomes 'pens' (I've seen this before).
'sermon' with half the letters taken is 'ser'.
'ser' going around 'pens' is 'SPENSER'.
'in' acts as a link.
(Other definitions for spenser that I've seen before include "He wrote" , "English poet of 'The Faerie Queene'" , "Edmund, 16th century poet" , "Author of "The Faerie Queen", d. 1599" , "Edmund ---, Eliz. poet" .)