My friend (the Prophet) advised me to do three things and I shall not leave them till I die, these are: To fast three days every month, to offer the Duha prayer, and to offer witr before sleeping.
Sahih al-Bukhari Book 19, Hadith 56
← Previous Hadith I never saw the Prophet (ﷺ) offering the Duha prayer but I always offer it.

Sahih al-Bukhari Book 19, Hadith 55 Next Hadith → 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."

Sahih al-Bukhari Book 19, Hadith 57