On the contrary, The Council of Chalons [*The quotation is from the Capitularies (Cap. 39) of Theodulf, bishop of Orleans (760-821) and is said to be found in the Corpus Juris, Cap. Solent, dist. 1, De Consecratione] says: "During Lent those are by no means to be credited with fasting who eat before the celebration of the office of Vespers," which in the Lenten season is said after the ninth hour. Therefore we ought to fast until the ninth hour.
I answer that, As stated above (AA[1],3,5), fasting is directed to the deletion and prevention of sin. Hence it ought to add something to the common custom, yet so as not to be a heavy burden to nature. Now the right and common custom is for men to eat about the sixth hour: both because digestion is seemingly finished (the natural heat being withdrawn inwardly at night-time on account of the surrounding cold of the night), and the humor spread about through the limbs (to which result the heat of the day conduces until the sun has reached its zenith), and again because it is then chiefly that the nature of the human body needs assistance against the external heat that is in the air, lest the humors be parched within. Hence, in order that those who fast may feel some pain in satisfaction for their sins, the ninth hour is suitably fixed for their meal.
Moreover, this hour agrees with the mystery of Christ's Passion, which was brought to a close at the ninth hour, when "bowing His head, He gave up the ghost" ( Jn. 19:30 ): because those who fast by punishing their flesh, are conformed to the Passion of Christ, according to Gal. 5:24, "They that are Christ's, have crucified their flesh with the vices and concupiscences."
Reply to Objection 1: The state of the Old Testament is compared to the night, while the state of the New Testament is compared to the day, according to Rom. 13:12, "The night is passed and the day is at hand." Therefore in the Old Testament they fasted until night, but not in the New Testament.
Reply to Objection 2: Fasting requires a fixed hour based, not on a strict calculation, but on a rough estimate: for it suffices that it be about the ninth hour, and this is easy for anyone to ascertain.
Reply to Objection 3: A little more or a little less cannot do much harm. Now it is not a long space of time from the sixth hour at which men for the most part are wont to eat, until the ninth hour, which is fixed for those who fast. Wherefore the fixing of such a time cannot do much harm to anyone, whatever his circumstances may be. If however this were to prove a heavy burden to a man on account of sickness, age, or some similar reason, he should be dispensed from fasting, or be allowed to forestall the hour by a little.
Whether it is fitting that those who fast should be bidden to abstain from flesh meat, eggs, and milk foods?
Objection 1: It would seem unfitting that those who fast should be bidden to abstain from flesh meat, eggs, and milk foods. For it has been stated above (A[6]) that fasting was instituted as a curb on the concupiscence of the flesh. Now concupiscence is kindled by drinking wine more than by eating flesh; according to Prov. 20:1, "Wine is a luxurious thing," and Eph. 5:18, "Be not drunk with wine, wherein is luxury." Since then those who fast are not forbidden to drink wine, it seems that they should not be forbidden to eat flesh meat.
Objection 2: Further, some fish are as delectable to eat as the flesh of certain animals. Now "concupiscence is desire of the delectable," as stated above (FS, Q[30], A[1]). Therefore since fasting which was instituted in order to bridle concupiscence does not exclude the eating of fish, neither should it exclude the eating of flesh meat.
Objection 3: Further, on certain fasting days people make use of eggs and cheese. Therefore one can likewise make use of them during the Lenten fast.
On the contrary, stands the common custom of the faithful.
I answer that, As stated above (A[6]), fasting was instituted by the Church in order to bridle the concupiscences of the flesh, which regard pleasures of touch in connection with food and sex. Wherefore the Church forbade those who fast to partake of those foods which both afford most pleasure to the palate, and besides are a very great incentive to lust. Such are the flesh of animals that take their rest on the earth, and of those that breathe the air and their products, such as milk from those that walk on the earth, and eggs from birds. For, since such like animals are more like man in body, they afford greater pleasure as food, and greater nourishment to the human body, so that from their consumption there results a greater surplus available for seminal matter, which when abundant becomes a great incentive to lust. Hence the Church has bidden those who fast to abstain especially from these foods.
Reply to Objection 1: Three things concur in the act of procreation, namely, heat, spirit [*Cf. P. I., Q. 118, A[1], ad 3], and humor. Wine and other things that heat the body conduce especially to heat: flatulent foods seemingly cooperate in the production of the vital spirit: but it is chiefly the use of flesh meat which is most productive of nourishment, that conduces to the production of humor. Now the alteration occasioned by heat, and the increase in vital spirits are of short duration, whereas the substance of the humor remains a long time. Hence those who fast are forbidden the use of flesh meat rather than of wine or vegetables which are flatulent foods.
Reply to Objection 2: In the institution of fasting, the Church takes account of the more common occurrences. Now, generally speaking, eating flesh meat affords more pleasure than eating fish, although this is not always the case. Hence the Church forbade those who fast to eat flesh meat, rather than to eat fish.
Reply to Objection 3: Eggs and milk foods are forbidden to those who fast, for as much as they originate from animals that provide us with flesh: wherefore the prohibition of flesh meat takes precedence of the prohibition of eggs and milk foods. Again the Lenten fast is the most solemn of all, both because it is kept in imitation of Christ, and because it disposes us to celebrate devoutly the mysteries of our redemption. For this reason the eating of flesh meat is forbidden in every fast, while the Lenten fast lays a general prohibition even on eggs and milk foods. As to the use of the latter things in other fasts the custom varies among different people, and each person is bound to conform to that custom which is in vogue with those among whom he is dwelling. Hence Jerome says [*Augustine, De Lib. Arb. iii, 18; cf. De Nat. et Grat. lxvii]: "Let each province keep to its own practice, and look upon the commands of the elders as though they were the laws of the apostles."