{They that hunger and thirst after righteousness} (hoi
pein(936e)tes kai dips(936e)tes t(886e) dikaiosun(886e)). Here Jesus turns one
of the elemental human instincts to spiritual use. There is in
all men hunger for food, for love, for God. It is passionate
hunger and thirst for goodness, for holiness. The word for
"filled" (chortasth(8873)ontai) means to feed or to fatten cattle
from the word for fodder or grass like  Mr 6:39  "green grass"
(chortos chl(9372)os).