Biblical brother embraces suitable leader (7)
I believe the answer is:
captain
'leader' is the definition.
(I know that captain is a type of leader)
'biblical brother embraces suitable' is the wordplay.
'biblical brother' becomes 'cain' (I've seen this in another clue).
'embraces' indicates putting letters inside.
'suitable' becomes 'apt' (apt means appropriate or fitting).
'cain' going around 'apt' is 'CAPTAIN'.
(Other definitions for captain that I've seen before include "Skip" , "Army rank" , "Commander of a ship" , "Leader" , "Naval rank" .)