Pope Shenouda III
Take the example of the fast of Nineveh:
The Bible says about the people of Nineveh that “every one turn from his evil way and from the violence that is in his hands.“ (Jon 3:8). For this reason, God did not destroy them when He “saw their works, that they turned from their evil way.” (Jon 3:10). The bible did not say: "when He saw their as sackcloth or their fast," but when he saw their repentance which was the principal element of their fast.