On After Death ~ St. John of Damascus, Metropolitan Hierotheos Vlachos, Metropolitan Hierotheos Vlachos & Father Seraphim Rose (St. Mark of Ephesus)

   One who has departed unrepentant and with an evil life cannot be helped by anyone in any way. But the one who has departed even with the slightest virtue, but who had no time to increase this virtue because of indolence, indifference, procrastination, or timidity, the Lord Who is a righteous judge and master will not forget such a one.

—(St John of Damascus)


Metropolitan Hierotheos Vlachos writes:

   Knowledge of God, as will be explained further on, is not intellectual, but existential. That is, one's whole being is filled with this knowledge of God. But in order to attain it, one's heart must have been purified, that is, the soul, nous and heart must have been healed. "Blessed are the pure in heart, for they shall see God."

 

(Orthodox Psychotherapy Section The Knowledge of God according to St. Gregory Palamas by Metropolitan Hierotheos Vlachos published by Birth of Theotokos Monastery,Greece (January 1, 2005) ISBN 978-960-7070-27-2)

Kyriacos C. Markides also confirms that purification is necessary in order to "see" God:

   The soul's journey toward God, I explained to Emily that day, must go through three identifiable and distinct stages. At first there is the state of catharsis, or the purification of the soul from egotistical passions It is then followed by the state of fotisis, or the enlightenment of the soul, a gift of the Holy Spirit once the soul has undergone its purification. Finally comes the stage of Theosis, union with God, as the final destination and ultimate home of the human soul. The last two stages are impossible to attain without having the soul first pass through the fires of catharsis from egotistical passions.

 

(Markides, The Mountain of Silence)

Father Seraphim Rose sums up the Patristic doctrine in this way:

   In the Orthodox doctrine, on the other hand, which St. Mark teaches, the faithful who have died with small sins unconfessed, or who have not brought forth fruits of repentance for sins they have confessed, are cleansed of these sins either in the trial of death itself with its fear, or after death, when they are confined (but not permanently) in hell, by the prayers and Liturgies of the Church and good deeds performed for them by the faithful.[6]

Saint Mark of Ephesus:

"But if souls have departed this life in faith and love, while nevertheless carrying away with themselves certain faults, whether small ones over which they have not repented at all, or great ones for which – even thought they have repented over them – they did not undertake to show fruits of repentance: such souls, we believe, must be cleansed from this kind of sin, but not by means of some purgatorial fire or a definite punishment in some place (for this, as we have said, has not been handed down to us). But some must be cleansed in they very departure from the body, thanks only to fear, as St. Gregory the Dialogist literally shows; while others must be cleansed after the departure from the body, either while remaining in the same earthly place, before they come to worship God and are honored with the lot of the blessed, or – if their sins were more serious and bind them, for a longer duration – they are kept in hell [i.e., Hades], but not in order to remain forever in fire and torment, but as it were in prison and confinement under guard." ^[7]

source:

https://orthodoxwiki.org/Purgatory