Is it permissible for someone who has been denied their rightful inheritance to enter the house of the person they believe possesses documents proving their usurped right without their knowledge, in order to find and give them to the rightful owner?

Al-Qurtubi warned against spying on homes, for entering a house without permission might lead to seeing the private parts of its occupants, as seeking permission was legislated for the sake of the gaze. Similarly, entering to search for documents without the homeowner's knowledge falls under the prohibited espionage, which Al-Nawawi interpreted as searching and investigating the hidden aspects of matters and secret news. The wronged person should refer their case to the Sharia court to claim their right, informing it that their opponent possesses documents proving their right.