In Exodus, he battles biblical kingdom (5)
I believe the answer is:
sheba
'biblical kingdom' is the definition.
(I've seen this in another clue)
'in exodus he battles' is the wordplay.
'in' indicates a hidden word.
'SHEBA' is hidden within 'exodus he battles'.
(Other definitions for sheba that I've seen before include "Ancient name of South Yemen" , "Old Yemen kingdom, its queen visited Solomon" , "Ancient Kingdom of the Sabeans" , "Solomon's guest" , "Hence Queen" .)