And thy meat which thou shall eat [shall be] by weight, twenty shekels a day,.... To eat bread by weight was a sign of a grievous famine; see Leviticus 26:26; a shekel, according to Josephus i, weighed four Attic drachms, or half an ounce, wherefore twenty shekels weighed ten ounces; so that the bread the prophet had to eat was but ten ounces a day:
from time to time shall thou eat it; at the certain time of eating, or but once a day; from a set time in one day to the same in another; as from morning to morning, or from noon to noon, or from evening to evening; see Jeremiah 37:21.
i Antiqu. l. 3. c. 8. sect. 2.