מדרש על יחזקאל 7:15

(Ibid. 25) "On the outside (of the city) the sword (of legions) shall devour (them) "— whence they derived: "In time of war, 'gather in' your legs" (i.e., stay at home); "in time of famine, 'spread out' your legs (and leave)." And thus is it written (Jeremiah 19:18) "If I go out to the field, there are the slain of the sword! And if I enter the city, there are the sick with famine!" And (Ezekiel 7:15) "Whoever is in the field will die by the sword, and whoever is in the city, famine and plague will consume him."