Had to return for a just a share of the old land (5)
I believe the answer is:
judah
'a share of the old land' is the definition.
I can't judge whether this defines the answer.
'had to return for a just' is the wordplay.
'to return' is a reversal indicator.
'for' is a charade indicator (letters next to each other) (I've seen this in other clues).
'a just' becomes 'ju' (I can't explain this - if you can you should believe this answer much more).
'had' written backwards gives 'dah'.
'dah' put after 'ju' is 'JUDAH'.
Can you help me to learn more?
(Other definitions for judah that I've seen before include "A son of Jacob and Leah" , "The most powerful of the twelve tribes of Israel" , "Tribe" , "One of 12 tribes of Israel" , "Jewish tribe,kingdom" .)