Sahih al-Bukhari 307
صحيح البخاري#307SahihNarrated Asma' bint Abi Bakr:A woman asked Allah's Messenger (ﷺ), "O Allah's Messenger (ﷺ)! What should we do, if the blood of menses falls on our clothes?" Allah's Messenger (ﷺ) replied, "If the blood of menses falls on the garment of anyone of you, she must take hold of the blood spot, rub it, and wash it with water and then pray in (with it)
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 6:12