Most advisable to accept the governor’s command (6)
I believe the answer is:
behest
'command' is the definition.
(behest is a kind of command)
'most advisable to accept the governor's' is the wordplay.
'most advisable' becomes 'best' (as in the best course of action).
'to accept' means one lot of letters goes inside another.
'the governor' becomes 'he' (I've seen this in other clues).
'best' going around 'he' is 'BEHEST'.
(Other definitions for behest that I've seen before include "Command, bidding" , "(At someone's) command" , "Command - Thebes (anag)" , "Order" .)