Musnad Ahmad 25:1400

Muhammad ibn Bakr narrated to us, Ibn Jurayj narrated to us, he said: 'Ata' informed me, he said: We were present with Ibn Abbas at the funeral of Maymunah, the wife of the Prophet, may God bless him and grant him peace, at Sarif. Ibn Abbas said: "This is the wife of the Messenger of God, may God bless him and grant him peace. So when you lift her bier, do not shake her, and do not jolt her, and be gentle, for he used to divide [his time] among eight, and he did not divide [his time] for one." 'Ata' said: "The one for whom he did not divide [his time] was Safiyyah bint Huyayy ibn Akhtab."