If a man beats his wife without reason can the wife beat him too to protect herself?
The wife shouldn't hit her husband back because will more likely than not escalate the matter, and result in greater harm to her and the marriage itself. Islam does not accept a husband beating a wife for any reason - abuse of either spouse is forbidden.
Men in an Islamic civilisation are granted judicial authority to discipline family members. The only time a man can discipline (not beat!) his wife is when she is doing something forbidden or being disobedient on a matter requiring obedience. If he is beating her, she needs serious help, from family members or authorities - and if the matter continues, she should consider parting ways via divorce.
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