Ibn Hibban

Ubaidullah bin Abdullah narrates from his father: I wanted to ask and I had a strong desire that I find someone who could tell me whether the Prophet Muhammad (peace be upon him) performed the Duha prayer, but I did not find anyone who could inform me about this except Lady Umm Hani bint Abi Talib (may Allah be pleased with her). She informed me that on the day of the conquest of Makkah, after the day had advanced, she came to the service of the Prophet Muhammad (peace be upon him). By the order of the Prophet (peace be upon him), a curtain was put up for him. He performed ghusl (ritual bath), then he stood up and performed eight rak‘ahs. I could not determine whether his standing in these rak‘ahs was longer, or his bowing was longer, or his prostration was longer, or whether all of these were about the same length. Lady Umm Hani (may Allah be pleased with her) states: I did not see the Prophet Muhammad (peace be upon him) performing these voluntary prayers before or after this.