Is a person rewarded if he divorces an unjust wife, or is it merely permissible?

The five rulings apply to divorce: it can be obligatory (wajib), forbidden (haram), recommended (mustahabb), disliked (makruh), or permissible (mubah).

It is permissible out of necessity, disliked when there is no necessity, recommended when the wife or husband is harmed by the continuation of the marriage, obligatory in the case of ila' if the husband refuses to return to his wife, and forbidden if it is an innovative divorce (bid'i).

Therefore, there is no sin on a man for divorcing his oppressive wife after exhausting all means of reconciliation and being unable to deter her or endure her, but we do not know of any specific reward for doing so.