 Pope Shenouda III
Pope Shenouda III
   The soul that is nourished is able to  support the body.
  This is  clearly seen during Passion Week  when asceticism becomes intense, with  long periods of abstinence.  Nevertheless, the body endures without  becoming tired because the soul  is nourished by the memories of  Christ's suffering by on Passion Week.  Bible readings, hymns, and rites  all focus the mind on Passion Week and  the suffering of our Lord.
  There are  times when a person may be so  absorbed by the satisfaction and pleasure  of what he reads that he may  forget about his craving for food so that  he can proceed with his  readings. The soul becomes nourished to the  extent that it sustains the  body, which does not feel any hunger.
  Therefore,  give the soul its nourishment  during a fast and rest assured that  nourishment of the soul gives the  body the strength it needs to endure  the fast. Moreover, fasting of the  body empower the soul, for the  spiritual action is intermingled with the  bodily and mental asceticism.  Prayers and masses during a fast are  more profoundduring  fasts for they emanate from a body, which has  submitted to the soul.  Your prayer becomes powerful since they emanate  from a heart abstained  from materialistic things and a soul abstained  from the worldly lusts.  Such as the vespers and midnight prayers  performed with a light body  abstaining from food.
  During the fasts, our Fathers concerned  themselves with the work of the soul.