by Augustine in a sermon (De orat. et Jejun. [*Serm.
lxxii] (ccxxx, de Tempore)): "Fasting cleanses the soul, raises the
mind, subjects one's flesh to the spirit, renders the heart contrite
and humble, scatters the clouds of concupiscence, quenches the fire
of lust, kindles the true light of chastity."

Reply Obj. 1: An act that is virtuous generically may be rendered
vicious by its connection with certain circumstances. Hence the text
goes on to say: "Behold in the day of your fast your own will is
founded," and a little further on (Isa. 58:4): "You fast for debates
and strife and strike with the fist wickedly." These words are
expounded by Gregory (Pastor. iii, 19) as follows: "The will
indicates joy and the fist anger. In vain then is the flesh
restrained if the mind allowed to drift to inordinate movements be
wrecked by vice." And Augustine says (in the same sermon) that
"fasting loves not many words, deems wealth superfluous, scorns
pride, commends humility, helps man to perceive what is frail and
paltry."

Reply Obj. 2: The mean of virtue is measured not according to
quantity but according to right reason, as stated in _Ethic._ ii, 6.
Now reason judges it expedient, on account of some special motive,
for a man to take less food than would be becoming to him under
ordinary circumstances, for instance in order to avoid sickness, or
in order to perform certain bodily works with greater ease: and much
more does reason direct this to the avoidance of spiritual evils and
the pursuit of spiritual goods. Yet reason does not retrench so much
from one's food as to refuse nature its necessary support: thus
Jerome says:* "It matters not whether thou art a long or a short time
in destroying thyself, since to afflict the body immoderately,
whether by excessive lack of nourishment, or by eating or sleeping
too little, is to offer a sacrifice of stolen goods." [*The quotation
is from the Corpus of Canon Law (Cap. Non mediocriter, De
Consecrationibus, dist. 5). Gratian there ascribes the quotation to
St. Jerome, but it is not to be found in the saint's works.] In like
manner right reason does not retrench so much from a man's food as to
render him incapable of fulfilling his duty. Hence Jerome says (in
the same reference) "Rational man forfeits his dignity, if he sets
fasting before chastity, or night-watchings before the well-being of
his senses."

Reply Obj. 3: The fasting of nature, in respect of which a man is
said to be