Narrated 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 and invited him to his house. He washed one side of a mat with water and the Prophet offered two Rakat on it.   So and so, the son of so and so, the son of Al-Jarud asked Anas,   Did the Prophet use to offer the Duha prayer?   Anas replied,   I never saw him praying (the Duha prayer) except on that day.