What is the ruling on espionage in Islam, and what is the punishment for a spy who violates the privacies of others under the pretext of fearing for them?

It is forbidden to spy on Muslims and to pry into their private affairs. Allah Almighty has prohibited this, stating: "O you who have believed, avoid much [negative] assumption. Indeed, some assumption is sin. And do not spy," and the Prophet, peace and blessings be upon him, said: "Do not spy and do not eavesdrop." The punishment for those who do this is disgrace in this world and humiliation in the Hereafter, as stated in the Hadith: "For whoever pries into their private affairs, Allah will pry into his private affairs, and whoever Allah pries into his private affairs, He will expose him in his own home." It is not permissible to spy except on criminals and thieves.