Musnad Ahmad 1153:2164

Yahya ibn Ishaq narrated to us, he said: Ja'far ibn Kaysan informed me, he said: 'Amrah al-'Adawiyyah narrated to me, she said: I heard 'Aishah saying: The Messenger of Allah, peace and blessings of Allah be upon him, said: "The one who flees from the plague is like the one who flees from the battle."