Yahya bin al-Jazzar (may Allah have mercy on him) said: Some of the Companions of the Prophet (peace and blessings be upon him) came to Sayyidah Umm Salamah (may Allah be pleased with her) and said: "O Mother of the Believers, narrate to us something about the Messenger of Allah (peace and blessings be upon him)." She said: "His outward and his inward (his open and his hidden state) were the same." Then Sayyidah Umm Salamah (may Allah be pleased with her) felt regret and said: "I have disclosed the secret of the Messenger of Allah (peace and blessings be upon him)." So when he (peace and blessings be upon him) came in, I told him (peace and blessings be upon him), and he (peace and blessings be upon him) said: "You did well."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 20044