What is the ruling of Islamic law regarding dealing with a person who discloses an matter that occurred between him and the questioner, and is his action considered slander (qadhf) that necessitates the imposition of a prescribed punishment (hadd) upon him?

We do not have the power to change Allah’s rulings. It is incumbent upon a Muslim to submit and surrender to what the Messenger of Allah, peace and blessings be upon him, has decreed, as stated in the Almighty's saying: "The only statement of the believers when they are called to Allah and His Messenger to judge between them is that they say, 'We hear and we obey.' And those are the successful." And His saying: "So let those who oppose his command beware, lest trial befall them or there strike them a painful punishment."