Spoke perhaps in a plea to higher authority (6)
I believe the answer is:
prayer
'plea to higher authority' is the definition.
I can't tell whether this defines the answer.
'spoke perhaps in a' is the wordplay.
'spoke perhaps' becomes 'ray' (I am not sure about this - if you are sure you should believe this answer much more).
'in' indicates putting letters inside.
'a' becomes 'per' (eg 'one a day' means 'one per day').
'ray' going inside 'per' is 'PRAYER'.
Can you help me to learn more?
(Other definitions for prayer that I've seen before include "Supplication [ital]" , "Litany" , "Words to a deity" , "Orison" , "Intended communication with a deity" .)