By H.G. Bishop Serapion
Great Lent is considered the holiest fast since our Lord Jesus Christ Himself had fasted it.
Therefore, during Great Lent we follow the example set by our Lord Jesus Christ, Who fasted on our behalf forty days and forty nights (Matt. 4: 2). Also during Holy Week, which comes after the 40 days, we live the Passion of Christ day-by-day and hour-by-hour. Because of the significance and holiness of Great Lent, the Church designated a week of preparation to precede the 40 days. The Church is teaching us to prepare for Great Lent in a spiritual manner. We fast to prepare ourselves for the 40 holy days. In fact, the preparatory week is not the only fast which the Church designated to get us ready for Great Lent and Holy Week. Two weeks prior to Great Lent there is Jonah’s Fast, also known as Nineveh’s Fast. It is a short fast, only three days, and it is a fast of repentance. During this fast, we live with Jonah his fasting and repentance in the whale’s belly. We also live with the Ninevites their fasting and repentance. Just as the fasting accompanied by repentance saved Jonah and the Ninevites from perdition, also our fasting accompanied by repentance will save us from eternal destruction and death due to sin. Great Lent is an Apostolic Fast: This article is copied from st-takla.org
It is mentioned in the Didskalia (chapter 18) the following: "Great Lent should be honored before Holy Week. It starts on the Monday following the Saturday and is completed on the Friday preceding Holy Week. After it, you must pay great attention to Holy Week and fast it with fear and piety." In Canon 69 from the Canons of our Fathers the Apostles, the following is mentioned: "Any bishop, priest, deacon, reader, or chanter who does not fast Great Lent or Wednesdays and Fridays shall be excommunicated, unless he has a physical ailment. As for a lay person, he shall be excluded."