The Sunday following Pentecost is dedicated to All Saints, both those who are known to us, and those who are known only to God. There have been saints at all times, and they have come from every corner of the earth. They were Apostles, Martyrs, Prophets, Hierarchs, Monastics, and Righteous, yet all were perfected by the same Holy Spirit.
The Descent of the Holy Spirit makes it possible for us to rise above our fallen state and to attain sainthood, thereby fulfilling God’s directive to “be holy, for I am holy” (Lev. 11:44, 1 Peter 1:16, etc.). Therefore, it is fitting to commemorate All Saints on the first Sunday after Pentecost.
This feast may have originated at an early date, perhaps as a celebration of all martyrs, then it was broadened to include all men and women who had borne witness to Christ by their virtuous lives, even if they did not shed their blood for Him.
Some of the saints are described as Confessors, a category which does not appear in the above lists. Since they are similar in spirit to the martyrs, they are regarded as belonging to the category of Martyrs. They were not put to death as the Martyrs were, but they boldly confessed Christ and came close to being executed for their faith. Saint Maximus the Confessor (January 21) is such a saint.
The order of these six types of saints seems to be based on their importance to the Church. The Apostles are listed first, because they were the first to spread the Gospel throughout the world.
The Martyrs come next because of their example of courage in professing their faith before the enemies and persecutors of the Church, which encouraged other Christians to remain faithful to Christ even unto death.
Although they come first chronologically, the Prophets are listed after the Apostles and Martyrs. This is because the Old Testament Prophets saw only the shadows of things to come, whereas the Apostles and Martyrs experienced them firsthand. The New Testament also takes precedence over the Old Testament.
The holy Hierarchs comprise the fourth category. They are the leaders of their flocks, teaching them by their word and their example.
The Monastic Saints are those who withdrew from this world to live in monasteries, or in seclusion. They did not do this out of hatred for the world, but in order to devote themselves to unceasing prayer, and to do battle against the power of the demons. Although some people erroneously believe that monks and nuns are useless and unproductive, Saint John Climacus had a high regard for them: “Angels are a light for monks, and the monastic life is a light for all men” (LADDER, Step 26:31).
The last category, the Righteous, are those who attained holiness of life while living “in the world.” Examples include Abraham and his wife Sarah, Job, Saints Joachim and Anna, Saint Joseph the Betrothed, Saint Juliana of Lazarevo, and others.
Excerpted from oca.org