Dear Dmitri and OorDeath,
An interesting point on merits and purgatory.
During the Council of Florence, St Mark Eugenikos, Archbishop of Ephesus, attended as, believe it or not, an Orthodox hierarch who was "pro-union" with the West.
St Mark believed that whatever else Rome held that was at variance with the East, God would eventually correct all if, and only if, the West would agree to formally remove the "Filioque" from the Creed.
St Mark required this as a minimum condition for unity.
He didn't even require the West to abjure its belief in the Filioque, only its removal from the Universal Creed held by all the Churches.
And we know the rest of the story here . . .
When it came to the subject of Purgatory and merits etc., St Mark realized that the West was quite different on this point as well.
Both Greek and Latin sides of the debate held that souls which were not purified, needed such before attaining union with God.
Both sides believed that prayer for the souls of the departed helped to bring them closer to God etc.
But the problem was that the West had come to understand the afterlife as defined in "places" with Heaven, Hell, Purgatory and, then, Limbo.
The East did not see the afterlife as defined in such categories since is does not believe that people go directly to Heaven until after the Second Coming when we will be reunited with our bodies.
Where the souls of the righteous go after death is a kind of "forecourt" of Heaven awaiting the Final Judgement.
In addition, prayer for the dead in the Eastern Orthodox Church is quite the dynamic thing where we also make prayer for the saints and even the Most Holy Mother of God (see the priest's prayers following the Canon in the Liturgy).
The West was married to a kind of "static" understanding of union with God, but it is not defined as doctrine and Western theologians are reexamining these points in the light of Eastern patristic teaching.
"Merits" is part of the "accountancy" perspective of the West that is truly foreign to the East.
St Seraphim of Sarov, however, did believe that our prayers, fasts and good works were part of our storing up of treasure in heaven, but that is as far as it went.
Alex