Sahih al-Bukhari 1179
صحيح البخاري#1179SahihNarrated Anas bin Sirin: I heard Anas bin Malik al-Ansari saying, "An Ansari man, who was very fat, said to the Prophet, 'I am unable to present myself for the prayer with you.' He prepared a meal for the Prophet (ﷺ) and invited him to his house. He washed one side of a mat with water and the Prophet (ﷺ) offered two Rakat on it." So and so, the son of so and so, the son of Al-Jarud asked Anas, "Did the Prophet (ﷺ) use to offer the Duha prayer?" Anas replied, "I never saw him praying (the Duha prayer) except on that day
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: 19:57