Religiously committed school entertaining archdeacon with a set of holy books (10)
I believe the answer is:
covenanted
'religiously committed' is the definition.
(as in the covenant)
'school entertaining archdeacon with a set of holy books' is the wordplay.
'school' becomes 'coed' (a co-educational school).
'entertaining' indicates putting letters inside.
'archdeacon' becomes 'ven' (abbreviation for The Venerable).
'with' says to put letters next to each other.
'set of holy books' becomes 'NT' (abbreviation for New Testament).
'ven'+'a'+'nt'='venant'
'coed' placed around 'venant' is 'COVENANTED'.
(Another definition for covenanted that I've seen is " Agreed".)