Whoever does not come to the rescue of a Muslim who is being dishonoured and disrespected, then Allah also does not provide him with succour in time of his need. And if anyone in such contingencies stands up in defence against the oppressor then Allah is aware of those who keep their duty (unto Him). Allah is Mighty Glorious.
To provide the greatest good of the greatest number for the cause of Islam and Muslims and for public welfare, even giving vital and timely information to avert a serious danger, is permissible in Islamic Shari’ah. Allah’s Messenger (peace and blessings of Allah be to him) sent Zubair to obtain secret information during the Battle of Ditch. We find many such instances in the life of the Blessed Messenger (peace and blessings of Allah be to him).
Once Hind bint Utaba, wife of Abū Sufian, complained to the Blessed Messenger about her husband in his absence. She told him that her husband was miser, and that he gave her a meagre amount for her and her children’s maintenance; and that the amount was far too inadequate for her bare necessities. Though it amounted to backbiting, the Blessed Messenger permitted her to relate it on the ground of oppression as the oppressed have the right to complain about any atrocity perpetrated on him/her.
With the intention of reformation and rectitude it is also permissible to relate the vices and defects to such persons as are helpful in eradicating or minimising the evil.