Musnad Ahmad 1153:1733

Waki’ narrated to us, Sufyan narrated to us, from ‘Abd al-Rahman ibn ‘Abis, from his father, from ‘Aishah, who said: "The family of Muhammad, may Allah bless him and grant him peace, never ate their fill of wheat bread for more than three [consecutive days]." She said: "And the Messenger of Allah, may Allah bless him and grant him peace, only forbade the meat of the sacrificial animals [to be kept] beyond three [days] due to the hardship of the people, then he granted a concession regarding it."