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 F9, 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 ) .
F9 Antiqu. l. 3. c. 8. sect. 2.