Pope Shenouda III
The proud Pharisee is another example of the unacceptable fast:
The Pharisee stood before God flaunting his virtues and saying: “I fast twice a week; I give tithes of all that I possess.” At the same time, he condemns the publican saying, “I am not like other men--robbers, evildoers, adulterers--or even like this tax collector.” (Luke 18:9-14). That is why he did not leave the temple justified, as was the case of the broken-hearted tax collector.
This example shows us that unless fasting is accompanied with humility and a contrite heart , then it is rejected by God. For without humility fasting is out of self righteous and disdain for others. (Luke 18:9).