St. Athanasius the Great ca. 297-373
[L]et us vie with each other in observing the purity of the fast 1 Cor. 9:24-27, by watchfulness in prayers, by study of the Scriptures, by distributing to the poor, and let us be at peace with our enemies. Let us bind up those who are scattered abroad, banish pride, and return to lowliness of mind, being at peace with all men, and urging the brethren unto love. Thus also the blessed Paul was often engaged in fastings and watchings, and was willing to be accursed for his brethren. Blessed David again, having humbled himself by fastings, used boldness, saying, ‘O Lord my God, if I have done this, if there is any iniquity in my hands, if I have repaid those who dealt evil with me, then may I fall from my enemies as a vain man. ‘ If we do these things, we shall conquer death; and receive an earnest of the kingdom of heaven. (Letter 14)