They gave advice so wise and so clear perhaps (7)
I believe the answer is:
oracles
'they gave advice so wise' is the definition.
The definition suggests an adverb but the answer is not.
'so clear perhaps' is the wordplay.
'perhaps' is an anagram indicator.
'so'+'clear'='soclear'
'soclear' anagrammed gives 'ORACLES'.
'and' is the link.
Can you help me to learn more?
(Other definitions for oracles that I've seen before include "They were consulted by ancient Greeks" , "Authoritative statements" , "Prophetic authorities" , "mysterious utterances" , "Authoritative sources" .)