Is a Muslim husband required to defend the honor of his wife if someone speaks negatively of her?

Question

When I read about marriages in Islam, sometimes I see this:

... A husband, therefore, has the responsibility of taking care of his wife, protecting her, defending her honor, and fulfilling her needs regarding her religion and her worldly life. ...
_IslamToday

He should defend her whenever she is slandered or spoken ill of behind her back.
_{Islam's Women}

However, I'm not sure how reliable these sources are. We also encounter the problem: How can I practically determine what "should" means?

Question: Is a Muslim husband required to defend the honor of his wife if someone speaks negatively of her?

I'm seeking some solid evidence (e.g. quotes from the Qur'an or Sunnah, or fatawa whose opinions are derived from reliable sources).

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The current answer seems to have misunderstood the question. I'm not asking if a husband is forbidden from speaking negatively about his wife; I'm asking if it's sin for him to not defend his wife when someone else speaks negatively of her. Or, at least, if it's largely expected of a husband to defend his wife's honor in such circumstances.

Answer 1

No matter if someone is your spouse or any other relative or even if you don't have any relation. In Islam it is forbidden to slander or speak ill of behind someone's back. You can read hadees about الغيبة

The person who slanders your spouse or anyone else and damages his/her reputations should be confronted and advised. It would be best if this advice is given discretely and in secret, since this is more desirable and usually proves more likely to be accepted.

Allah says:

And those who speak evil things of the believing men and the believing women without their having earned (it), they are guilty indeed of a false accusation and a manifest sin. [Sûrah al-Ahzâb: 58]

An advice once given to me was to start talking about good qualities of a person if he/she is being slandered in a company.

And Allah knows best