Musnad Ahmad 33:363

Abu Abd al-Rahman narrated to us, Sa'id narrated to us, 'Amr ibn Jabir narrated to me, he said: I heard Jabir ibn Abdullah al-Ansari 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 line, and the one who remains patient in it is like the one who remains patient in the battle line."