Musnad Ahmad 1153:818

Zayd ibn al-Hubab narrated to us, he said: Mu'awiyah ibn Salih narrated to us, he said: Abu al-Zahiriyah informed me, from 'Aishah, that she said: A woman gifted her dates in a tray, and she ate some of them and some remained. She said: "I adjure you to eat the remainder of it." The Messenger of Allah (peace and blessings of Allah be upon him) said: "Fulfill her oath, for the sin is upon the one who is being adjured."