The practice of Christian abstinence from food of animal origin on Wednesday and Friday dates back to the first centuries of Christianity. You need to understand that the post for the Orthodox involves not only the eating of certain foods, but the memory of the great events of new Testament history.

So, on Wednesday, Orthodox Christians fast in memory of the betrayal of Jesus by Judas. The Scriptures of the New Testament announces that on Wednesday before the Jewish Passover Judas Iscariot sold Christ for thirty pieces of silver to the Pharisees and Jewish teachers of the law. On this day the Orthodox people are fasting in memory of this sad event.

The biblical story leads to why the Orthodox fast on Friday. It was the day of the week was the death of the Lord Jesus. On Friday Christ was crucified. According to the teachings of the Church on this day the Savior of the world died for the sins of all mankind. A pious Christian must be mindful of the price which he got salvation. So Friday for the Orthodox is a time of special bodily and spiritual abstinence.

It should be noted that the Church's Charter stipulates a different degree of abstinence of Wednesdays and Fridays. So, if these days fall on a multi-day posts, it is prohibited to eat fish. In Wednesdays and Fridays, not attributable to fasting, eating of fish is allowed.