John Cassian
Patristic
c. A.D. 360–435
“You see, then, that fasting is certainly not considered by the Lord as a thing that is good in its own nature, because it becomes good and well-pleasing to God not by itself but by other works. Again, from the surrounding circumstances it may be regarded as not merely empty but hateful, as the Lord says: "When they fast, I will not hear their prayers."”