According to Orthodox theology, the purpose of the Christian life is to attain theosis, the mystical union of mankind with God. This union is understood as both collective and individual. St. Athanasius of Alexandria wrote concerning the Incarnation that, "He (Jesus) was made man that we might be made god (θεοποιηθῶμεν)." See 2 Peter 1:4, John 10:34–36, Psalm 82:6. The entire life of the church is oriented towards making this possible and facilitating it.
In the Orthodox Church the terms "mystery" or "the mysteries" refer to the process of theosis. While it is understood that God theoretically can do anything instantly and invisibly, it is also understood that he generally chooses to use material substance as a medium in order to reach people. The limitations are those of mankind, not God. Matter is not considered to be evil by the Orthodox. Water, oil, bread, wine, etc., all are means by which God reaches out to allow people to draw closer to him. These mysteries are surrounded by prayer and symbolism so that their true meaning will not be forgotten.
Those things which in the West are often termed sacraments or sacramentals are known among the Orthodox as the "sacred mysteries". While the Roman Catholic Church numbers seven sacraments, and many Protestant groups list two (Baptism and the Eucharist) or even none, the Orthodox do not limit the number. However, for the sake of convenience, catechisms will often speak of the seven Great Mysteries. Among these are Holy Communion (the most direct connection), Baptism, Chrismation, Confession, Unction, Matrimony, and Ordination. But the term also properly applies to other sacred actions such as monastic tonsure or the blessing of holy water, and involves fasting, almsgiving, or an act as simple as lighting a candle, burning incense, praying or asking God's blessing on food.
Here you will find a miscellaneous compendium of pages that answer common questions about Orthodoxy answered by present pastors as well as venerated teachers who have fallen asleep in the Lord. These take the form of basic question and answers (Fr. Robert Arida) to articles on various topics (Fr. Alexander Men), to full classic texts on theological topics (Fr. Georges Florovsky).