The Prophet ﷺ entrusted me with a secret that I will never disclose to anyone until I meet him.
حدثنا هاشم بن القاسم حدثنا عيسى يعني ابن طهمان قال
إن للنبي ﷺ عندي سرا لا أخبر به أحدا أبدا حتى ألقاه
No references are available.
Its isnad is sahih. Isa bin Tahman has been the subject of some criticism, but it does not cause harm. The hadith was mentioned previously in full, see also Sahih Muslim 4/1929, no. 2482, in the book on the merits of the Companions, in the chapter on the merits of Anas.