St. Ambrose on Fasting

St. Ambrose of Milan ca. 339-397

And what is the intention of the Scripture which teaches us that Peter fasted, and that the revelation concerning the baptism of Gentiles was made to him when fasting and praying, Acts 10:10 except to show that the Saints themselves advance when they fast. Finally, Moses received the Law when he was fasting; Exodus 34:28 and so Peter when fasting was taught the grace of the New Testament. Daniel too by virtue of his fast stopped the mouths of the lions and saw the events of future times. Daniel vi.-vii And what safety can there be for us unless we wash away our sins by fasting, since Scripture says that fasting and alms do away sin? Tobit 12:8-9

Who then are these new teachers who reject the merit of fasting? Is it not the voice of heathen who say, Let us eat and drink? whom the Apostle well ridicules, when he says: If after the manner of men I have fought with beasts at Ephesus, what advantages it me if the dead rise not? Let us eat and drink, for tomorrow we die. 1 Corinthians 15:32 That is to say, What profited me my contention even unto death, except that I might redeem my body? And it is redeemed in vain if there is no hope of the resurrection. And, consequently, if all hope of the resurrection is lost, let us eat and drink, let us not lose the enjoyment of things present, who have none of things to come. It is then for them to indulge in meats and drinks who hope for nothing after death.

Rightly then does the Apostle, arguing against these men, warn us that we be not shaken by such opinions, saying: Be not deceived, evil communications corrupt good manners. Be righteously sober and sin not, for some have no knowledge of God. 1 Corinthians 15:33 Sobriety, then, is good, for drunkenness is sin. (Epistle 63: 16-18)