Musnad Ahmad 1276:3

Muhammad and Hajjaj narrated to us, they said: Shu'bah narrated to us, from Qatadah, from Abu Ayyub, from Juwayriyah bint al-Harith, she said: The Prophet, peace and blessings of Allah be upon him, entered upon her on a Friday while she was fasting. He said to her: "Did you fast yesterday?" She said: "No." He said: "Do you intend to fast tomorrow?" She said: "No." The Prophet, peace and blessings of Allah be upon him, said: "Then break your fast."