صحيح مسلم

Anas reported: Allah's Messenger (ﷺ) came to me as I was playing with playmates. He greeted and sent me on an errand and I made delay in going to my mother. When I came to her she said: What detained you? I said: Allah's Messenger (ﷺ) sent me on an errand. She said: What was the purpose? I said: It is something secret. Therupon she said: Do not then divulge the secret of Allah's Messenger (ﷺ) to anyone. Anas said: By Allah, if I were to divulge it to anyone, then, O Thabit, I would have divulged it to you.