Musnad Abu Ya'la al-Mawsili 148:87

Muhammad ibn Isma'il ibn Abi Samina narrated to us, Abd al-Rahman ibn Mahdi narrated to us, Aban ibn Khalid narrated to us, from Ubayd Allah ibn Rawaha, from Anas ibn Malik, who said: The Messenger of Allah, peace and blessings of Allah be upon him, would not pray the Duha (forenoon) prayer unless he was arriving from a journey or departing for one.