Share out every set of holy books (5)
I believe the answer is:
allot
'share out' is the definition.
(synonyms)
'every set of holy books' is the wordplay.
'every' becomes 'all' (similar in meaning).
'set of holy books' becomes 'OT' (abbreviation for Old Testament).
'all'+'ot'='ALLOT'
(Other definitions for allot that I've seen before include "Assign or distribute" , "Assign a share" , "Designate; sounds like much" , "Allocate" , "Dispense or distribute" .)