For the Orthodox Christian, doctrine is very important, as it is the very means by which we can know the truth of reality, which God has revealed to us. Christian doctrine forms the foundation that we need to understand God, salvation, sin, man's state of affairs in the created world, and many other things.
Salvation:
• Theosis
Sacraments (Mysteries):
• Baptism
• Holy Communion (The Eucharist)
• Holy Unction (Anointing of the Sick)
• Ordination (Apostolic Succession, Holy Orders, and the Priesthood)
Christology and the Nature of God:
• Jesus is God
• Miaphysitism (One Incarnate Nature)
• Virgin Birth
Tradition:
• Deuterocanonicals ("Apocrypha")
• Holy Bible
• Iconography (Statues, Paintings, and Images)
• Intercession of the Saints (Praying to the Saints)
• Oral Tradition
• Relics
• Septuagint (LXX)
• Textus Receptus (TR)
Christian Life:
• Fasting
• Modest Apparel
• Prayer
• Sign of the Cross
Other:
• Guardian Angels
• Hell
• Mary
• Young Earth Creationism