Do you fast? Give me proof of it by your works. If you see a poor man, take pity of him. If you see a friend being honored, do not envy him. Do not let only your mouth fast, but also to eye, the ear, and the feet, and the hands, and all members of our bodies. Let the hands fast, by being free of avarice [greed]. Let the eyes fast by disciplining it not to glare at that which is sinful. Let the ear fast, by not listening to evil talk and gossip. Let the mouth fast from foul words and criticism. For what good is it if we abstain from fowl and fishes, but bite and devour one another?

St John Chrysostom, 4th century