Catholic Encyclopedia

The mystery of the Trinity is the central mystery of Christian faith. The Father is unbegotten; the Son is eternally begotten of the Father; the Holy Spirit proceeds from the Father and the Son. The three Persons are consubstantial, equal in majesty, and distinct in relation.

Reference: CCC 232–267

“And the Word became flesh and dwelt among us” (John 1:14). In Jesus Christ, divinity and humanity are united in one Person. The Incarnation reveals God’s humility and love, and makes possible our redemption and divinization by grace.

Reference: CCC 456–483; John 1:14

By His free obedience unto death on the Cross, Jesus offers the perfect sacrifice for sin. The Resurrection confirms His victory. Catholics enter this mystery especially through the Mass, which re-presents the one sacrifice of Calvary in an unbloody manner.

Reference: CCC 595–623; Heb 9–10

Baptized believers are living members of Christ’s Body. The Church is one, holy, catholic, and apostolic. She is both visible society and spiritual communion, pilgrim on earth and already united with the saints in heaven.

Reference: CCC 787–796; Eph 1:22–23

Tradition is not a rival to Scripture but its living context. Through liturgy, teaching, and the witness of the saints, the Church hands on what she has received from the apostles.

Reference: CCC 75–83; 2 Thess 2:15

Mary is Mother of God, ever-virgin, Immaculate Conception, and assumed into heaven. At the Cross she became Mother of the disciples. Catholics honor her with hyperdulia—highest veneration short of the worship due to God alone.

Reference: CCC 963–975

Sacraments of initiation: Baptism, Confirmation, Eucharist. Sacraments of healing: Penance, Anointing of the Sick. Sacraments at the service of communion: Holy Orders and Matrimony. Each confers grace and configures the Christian to Christ.

Reference: CCC 1210–1666

The Church Militant, Suffering, and Triumphant are one Body. We pray for the dead, ask the saints’ intercession, and share spiritual goods. This communion is celebrated especially in the Eucharist and All Saints/All Souls.

Reference: CCC 946–962

Purgatory is not a “second chance,” but the completion of sanctification. The Church’s prayer, especially the Mass, assists the holy souls. Scripture’s teaching on purification and praying for the dead supports this doctrine (cf. 2 Macc 12:46; 1 Cor 3:15).

Reference: CCC 1030–1032; 2 Macc 12:46

Christ gave Peter a unique primacy among the apostles (Mt 16:18–19; Jn 21:15–17). The Bishop of Rome inherits this ministry of unity. Papal teaching, when definitive, is protected by the Holy Spirit from error in faith and morals.

Reference: CCC 880–896

Key principles include the dignity of the human person, solidarity, subsidiarity, preferential option for the poor, and care for creation. Landmark documents include Rerum Novarum, Laborem Exercens, Centesimus Annus, and Laudato Si’.

Reference: Compendium of the Social Doctrine of the Church

Vatican II produced constitutions on the liturgy (Sacrosanctum Concilium), revelation (Dei Verbum), the Church (Lumen Gentium), and the Church in the modern world (Gaudium et Spes). It called for a deeper biblical and liturgical life among the faithful.

Reference: Vatican II documents

From Nicaea (325) to Vatican II, councils have clarified Christology, Mariology, the sacraments, and Church life. Their dogmatic definitions bind the faithful when confirmed by the Pope.

Reference: CCC 884

Angels are messengers and guardians. Demons are fallen angels who tempt but cannot force the will. The Church teaches sober spiritual warfare through prayer, sacraments, and trust in Christ—not superstition.

Reference: CCC 328–336, 391–395

Particular judgment follows death; general judgment comes at Christ’s return. Heaven is eternal communion with God; hell is definitive self-exclusion from God. Hope of heaven and holy fear of hell shape Christian conversion.

Reference: CCC 1020–1060