Musnad Abu Ya'la al-Mawsili 149:87

Abu Bakr ibn Abi Shaybah narrated to us, Hafs narrated to us, from Ibn Jurayj, from ‘Ata’, from ‘Ubayd ibn ‘Umayr, from ‘A’ishah, who said: I did not see the Prophet, may Allah bless him and grant him peace, hasten toward any of the supererogatory prayers as he hastened toward the two rak'ahs of the dawn, nor toward any spoils of war.