Old man’s wise quotation? (7)
I believe the answer is:
passage
'quotation?' is the definition.
(quotation is a kind of passage)
'old man's wise' is the wordplay.
'old man's' becomes 'pas' (both can mean father).
'wise' becomes 'sage' ('sage' can be similar in meaning to 'wise').
'pas'+'sage'='PASSAGE'
(Other definitions for passage that I've seen before include "Section of text; journey" , "Literary extract" , "Sea/air journey" , "equestrian manoeuvre" , "course" .)