Orthodox Religion cheat sheet

The Orthodox canon of the Old Testament follows the Septuagint (LXX) and includes the Deuterocanonical books (e.g., Wisdom, Sirach, Tobit, Judith, 1–2 Maccabees); these are read liturgically but not used for doctrine in the same way as the Hebrew canon.

The New Testament canon of 27 books was formally recognized in the East by the Council of Carthage (397) and later ratified by the Quinisext Council (Trullo, 692), which listed the canonical books.

The four Gospels are Matthew, Mark, Luke, John; the Pauline corpus includes 14 epistles (Hebrews is traditionally attributed to Paul), and the Catholic Epistles are James, 1–2 Peter, 1–2–3 John, Jude.

The Synoptic Gospels (Matthew, Mark, Luke) share a common outline and often verbal agreement; John is distinct in structure and theology, and its Gospel is read liturgically from Pascha to Pentecost.

The Psalter is the most frequently used Old Testament book in Orthodox worship; it is divided into 20 kathismata for weekly recitation and forms the core of the daily offices.

The Septuagint numbering of the Psalms differs from the Hebrew (e.g., LXX Ps 9 = Heb 9–10; LXX Ps 113 = Heb 114–115; LXX Ps 114–115 = Heb 116; LXX Ps 146–147 = Heb 147), affecting liturgical citations.

The Sermon on the Mount (Matt 5–7) and the Lukan Sermon on the Plain (Luke 6) present the ethical core of the Gospel; the Beatitudes are read at every Divine Liturgy as the third antiphon.

Typology interprets Old Testament events as prefigurations of Christ (e.g., the Passover lamb, the brazen serpent, Jonah's three days), a method used by the Fathers and in hymnography.

The Nicene-Constantinopolitan Creed (381) is the definitive Trinitarian symbol; it affirms one essence (ousia) in three hypostases-Father, Son, and Holy Spirit-and is recited at every Divine Liturgy.

The First Ecumenical Council (Nicaea, 325) condemned Arianism and defined the Son as homoousios (consubstantial) with the Father; the Second (Constantinople, 381) condemned Pneumatomachians and expanded the creed on the Holy Spirit.

The Third (Ephesus, 431) condemned Nestorianism and affirmed Mary as Theotokos; the Fourth (Chalcedon, 451) defined Christ as one hypostasis in two natures, unconfused, unchanging, undivided, inseparable.

The Fifth (Constantinople II, 553) condemned the Three Chapters and reaffirmed Chalcedon; the Sixth (Constantinople III, 680–681) condemned Monothelitism, affirming two wills and two energies in Christ.

The Seventh (Nicaea II, 787) restored the veneration of icons, distinguishing latreia (worship due to God alone) from proskynesis (veneration given to icons, the Cross, and saints).

The Filioque clause (Latin: "and the Son") was added to the Creed in the West and is rejected by the Orthodox as an unauthorized addition and a distortion of the monarchy of the Father.

Theosis (deification) is the goal of Christian life: participation in the divine energies, not the essence, as taught by St. Athanasius, St. Gregory Palamas, and the Palamite councils of the 14th century.

The distinction between the divine essence (ousia) and energies (energeiai) is dogma in the Orthodox Church, defined in the councils of 1341, 1347, and 1351, and articulated by St. Gregory Palamas.

The Divine Liturgy has two main parts: the Liturgy of the Catechumens (readings, litanies, Little Entrance) and the Liturgy of the Faithful (Great Entrance, Anaphora, Communion); the faithful must be baptized and fasting.

The three principal Liturgies are those of St. John Chrysostom (most Sundays), St. Basil the Great (Sundays of Great Lent, Christmas, Theophany, Holy Thursday/Saturday), and the Presanctified Gifts (weekdays of Great Lent).

The seven mysteries (sacraments) are Baptism, Chrismation, Eucharist, Confession, Marriage, Ordination, and Anointing of the Sick; Baptism and Chrismation are administered together, and infants receive all three.

The Eucharist is the center of Orthodox life: the bread and wine are changed into the Body and Blood of Christ by the Holy Spirit (epiklesis) after the Words of Institution; communion is received under both species.

Baptism is by triple immersion in the name of the Father, Son, and Holy Spirit; Chrismation (confirmation) immediately follows, sealing the gift of the Holy Spirit with holy chrism consecrated by a bishop.

Confession is made to a priest, who acts as witness and spiritual father; absolution is pronounced by the priest, and the penitent receives a penance (epitimia) according to the canon.

Marriage is celebrated with the betrothal and crowning services; the crowns symbolize martyrdom and the kingdom, and the common cup is shared; divorce is permitted only by economia for adultery or grave danger.

Ordination (cheirotonia) is performed by a bishop at the Divine Liturgy; only males may be ordained, and the orders are bishop, priest (presbyter), and deacon; minor orders include reader and subdeacon.

Apostolic era: Pentecost (c. 30 AD), the Council of Jerusalem (c. 49 AD) decided Gentile converts need not be circumcised; the four Gospels and Pauline epistles were written between c. 50 and 100 AD.

Persecutions: Nero (64), Domitian (c. 95), Trajan (c. 112, Pliny's letter), Decius (250), Diocletian (303–311); the Edict of Milan (313) by Constantine and Licinius granted toleration.

Constantine convened the First Ecumenical Council at Nicaea in 325; he moved the capital to Constantinople in 330, and Theodosius I made Nicene Christianity the state religion (Edict of Thessalonica, 380).

The Christological controversies: Apollinarianism (condemned 381), Nestorianism (431), Monophysitism (451), Monothelitism (681); the Oriental Orthodox churches separated after Chalcedon (451).

The Great Schism of 1054: mutual excommunications between Cardinal Humbert and Patriarch Michael Cerularius; the primary issues were papal primacy and the Filioque, with cultural and political tensions.

The Photian Schism (863–867) was a temporary rupture over the Bulgarian Church and papal jurisdiction; it was resolved after Photius's reinstatement, but the Filioque dispute remained.

The Quinisext Council (Trullo, 692) issued 102 canons completing the Fifth and Sixth Councils; it established the Pentarchy (five patriarchates) and regulated clerical discipline.

Monasticism began with St. Anthony the Great (c. 251–356) and was organized by St. Pachomius (c. 292–348); St. Basil the Great wrote the monastic rules that govern Orthodox monasticism.

The Fall of Constantinople (1453) placed the Ecumenical Patriarchate under Ottoman rule; the millet system gave the patriarch civil authority over Orthodox subjects, and the Church survived through the Ottoman period.

Autocephaly (self-governing status) is granted by a mother church and recognized by the others; the order of honor among autocephalous churches is Constantinople, Alexandria, Antioch, Jerusalem, Russia, and so on.

The Russian Church became autocephalous in 1448 (de facto) and was recognized by Constantinople in 1589 as a patriarchate; the Moscow Patriarchate was abolished by Peter the Great (1721) and restored in 1917.

The Greek Church declared autocephaly in 1833 and was recognized by Constantinople in 1850; other Balkan churches (Serbia 1879, Romania 1885, Bulgaria 1945) followed similar patterns.

The Orthodox Church in America (OCA) received autocephaly from the Moscow Patriarchate in 1970; its autocephaly is not universally recognized by all Orthodox churches.

The Great and Holy Council of Crete (2016) was convened by the Ecumenical Patriarch; four patriarchates (Antioch, Russia, Georgia, Bulgaria) did not attend, and its documents are not universally accepted.

The calendar controversy (1920s) arose when some churches adopted the Revised Julian calendar for fixed feasts; the Old Calendarists rejected the change, creating schisms in Greece, Romania, and elsewhere.

Ecumenical dialogue: the Joint International Commission for Theological Dialogue between the Orthodox and Roman Catholic Churches (1980–) has addressed primacy, the Filioque, and the sacraments; the Orthodox participate in the WCC.

St. Athanasius (c. 296–373): On the Incarnation and Against the Arians; defended Nicaea, taught theosis ("God became man that man might become god"), and wrote the Life of Antony.

St. Basil the Great (c. 330–379): On the Holy Spirit, monastic rules, and the Liturgy; defended the divinity of the Holy Spirit and organized philanthropy (Basiliad).

St. Gregory the Theologian (c. 329–390): Five Theological Orations, defended the Trinity and the divinity of the Holy Spirit; presided over the Second Ecumenical Council.

St. John Chrysostom (c. 347–407): On the Priesthood, homilies on Scripture, and the Liturgy; exiled for criticizing the empress Eudoxia; his paschal homily is read at every Pascha.

St. Maximus the Confessor (c. 580–662): defended two wills in Christ against Monothelitism; his Ambigua, Centuries on Love, and Mystagogy synthesize patristic theology and asceticism.

St. John of Damascus (c. 675–749): Exact Exposition of the Orthodox Faith, defended icons in Three Treatises; his work systematized Eastern theology and is a key source for dogmatics.

St. Gregory Palamas (1296–1359): defended hesychasm and the distinction between essence and energies; his Triads and the Hagioritic Tome shaped Palamite theology.

Ascetic theology: the three stages of purification (katharsis), illumination (photismos), and union (theosis); the Jesus Prayer ("Lord Jesus Christ, Son of God, have mercy on me") is central to hesychast practice.

The canonical corpus includes the Apostolic Canons (85), the canons of the Ecumenical Councils, the canons of local councils (e.g., Carthage, Ancyra), and the Church Fathers (e.g., Basil's 92 canons); the Rudder (Pedalion) is the standard compilation.

The principle of economia (economy) allows a bishop to relax the strict application of a canon for the salvation of a soul; akribeia (strictness) is the norm, and economia is an exception.

The Pentarchy (Rome, Constantinople, Alexandria, Antioch, Jerusalem) was established by Justinian and ratified by Trullo (692); after the schism, the five patriarchates remained the ideal order.

Autocephaly is granted by the mother church and recognized by the others; autonomy is limited self-governance under a mother church; the Ecumenical Patriarch has the right to convene pan-Orthodox councils.

Canon 28 of Chalcedon granted Constantinople privileges equal to Rome and jurisdiction over the dioceses of Pontus, Asia, and Thrace; Rome rejected this canon, a key source of the primacy dispute.

The prohibition of simony (Acts 8:18–24) is enforced by canon; clergy may not charge for ordination or sacraments, and bishops must be elected canonically.

Marriage impediments: consanguinity to the fourth degree (civil law often to the sixth), affinity, and spiritual kinship (godparents); second marriages are permitted with penance, third with greater penance, fourth forbidden.

The canons forbid the transfer of clergy between dioceses without canonical release (Apostolic Canon 15); a bishop must be celibate, and priests may marry before ordination but not after.

Icons are theologically justified by the Incarnation: God became visible in Christ, so He can be depicted; the Seventh Ecumenical Council (787) restored icons and distinguished veneration (proskynesis) from worship (latreia).

The iconostasis separates the nave from the sanctuary; it developed from the templon and has three doors (Royal Doors in the center, north and south deacon doors) and tiers of icons (Savior, Theotokos, saints, feasts).

Iconographic conventions: reverse perspective (lines converge toward the viewer), gold leaf for divine light, stylized faces, and no shadows; the icon is a window into heaven, not a realistic portrait.

The Theotokos is depicted with the Christ Child in the Hodegetria (She who shows the Way) or Eleusa (Tenderness) types; the Orans (praying) type shows her without the Child, often in the apse.

The Pantocrator (Almighty) is the central image in the dome; Christ holds the Gospel and blesses with the right hand, with the letters IC XC and the halo inscribed with the cross.

The Cross: the Orthodox cross often has a slanted footrest (the suppedaneum) and the INBI inscription; the three-bar cross is Russian, and the eight-pointed cross is common in Slavic traditions.

Liturgical colors: gold for feasts of Christ, white for Theophany and Pascha, blue for feasts of the Theotokos, red for martyrs and Pascha, green for Pentecost and Palm Sunday, purple for Lent and the Cross.

The narthex, nave, and sanctuary correspond to the stages of spiritual life; the dome represents heaven, the apse the cave of Bethlehem, and the altar the table of the Last Supper.

Roman Catholicism: the Filioque, papal infallibility (1870), and the dogmas of the Immaculate Conception (1854) and Assumption (1950) are not accepted by the Orthodox; the Orthodox reject the universal jurisdiction of the Pope.

Protestantism: the Orthodox reject sola scriptura, sola fide, and sola gratia as one-sided; they affirm Scripture and Tradition, faith and works, grace and freedom, and the sacraments as means of grace.

Oriental Orthodox (Coptic, Syriac, Armenian, Ethiopian, Eritrean, Indian): separated after Chalcedon (451) over the two natures; modern dialogues have reached agreement on the Christological formula (1990).

The Assyrian Church of the East (Nestorian) separated after Ephesus (431); the 1994 Common Christological Declaration with the Catholic Church resolved the Nestorian dispute, and dialogue with the Orthodox continues.

The Anglican–Orthodox dialogue (since 1973) has produced agreed statements on the Trinity, Christology, and the Church; the ordination of women and the 1990s innovations have strained relations.

The World Council of Churches (WCC, founded 1948) includes most Orthodox churches; the Orthodox participate but do not recognize the WCC as a church and reject intercommunion without unity in faith.

The Joint International Commission for Orthodox–Catholic Dialogue (1980) issued the Balamand Statement (1993) on uniatism, rejecting it as a method of union; the Ravenna Document (2007) addressed primacy.

The Orthodox Church does not recognize the validity of Anglican or Protestant orders; it may accept converts by chrismation or baptism depending on the church and the local bishop's economia.

The Ten Commandments and the Sermon on the Mount are the foundation of Orthodox ethics; the virtues (faith, hope, love, humility, temperance) are cultivated through prayer, fasting, and the sacraments.

Fasting rules: Great Lent (40 days plus Holy Week) is the strictest; Wednesdays and Fridays are fast days; the Nativity Fast (40 days), Apostles' Fast, and Dormition Fast are also observed; dispensation is by the bishop or priest.

The Jesus Prayer and the practice of the presence of God are central to pastoral counseling; the spiritual father (geron) guides the penitent, and the sacrament of confession is the primary means of healing.

Bioethics: the Orthodox Church opposes abortion, euthanasia, and the death penalty in principle; it permits organ donation and medical treatment, and it blesses the use of technology for healing.

Marriage and family: the Church blesses marriage as a mystery, opposes same-sex unions and surrogate motherhood, and permits divorce only by economia for adultery or grave danger to the spouse.

Social ethics: the Church condemns poverty, exploitation, and racism; it supports religious freedom, the protection of creation, and the dignity of the human person created in the image of God.

Pastoral care of the sick: the mystery of anointing (unction) is celebrated for healing of soul and body; it may be repeated, and it is not reserved for the dying.

The principle of synergeia (cooperation) between divine grace and human freedom governs Orthodox ethics; the person is not passive but cooperates with grace, and the goal is theosis.