What is stated in the Qur'an and Sunnah regarding the disclosure of entrusted secrets?

Secrets are trusts and covenants that must be preserved. Disclosing them is a betrayal and a breach of covenant. Allah Almighty rebuked Aisha and Hafsa for disclosing a secret of the Prophet, peace be upon him, and their punishment was the Prophet's month-long اعتزال (seclusion/withdrawal) from them. Ibn Hajar mentioned that it involved "punishment for disclosing a secret, befitting the one who disclosed it."

The prohibition becomes more severe when disclosing secrets that harm Muslims or expose their private matters. Whoever uncovers the private matters of people without their permission may have his eye put out without blood money or retaliation. And whoever eavesdrops on a conversation of people who dislike him doing so, molten lead will be poured into his ear on the Day of Judgment.

One of the greatest betrayals of trusts is a man disclosing his wife's secret. Among the Arabs' advice to the bride was not to disclose her husband's secret. For disclosing secrets is a sign of hypocrisy, as it falls under the betrayal of trusts.

It is not a condition for it to be stated that the كلام (words/conversation) is a secret; if a man speaks a statement then turns away, it is a trust. This is because the speaker's turning away informs the listener that he fears someone else hearing his words, and that he has confided his secret in him, thus he must conceal it.