What do Catholics Believe?

Related Article: "I believe in God, the Father Almighty, creator of heaven and earth."
Explanation: We first and foremost express our belief in God, who is Almighty; in this attribute are summarized all his other attributes. We believe in one God, but three divine Persons: Father, Son, and Holy Spirit. The Son is the Father's knowledge of himself, and from that knowledge proceeds the Holy Spirit. The Persons of the Trinity are not the same, but distinct, but they also exist in relation to each other. God--Father, Son, and Holy Spirit--created the heavens and the earth purely out of love. God had no need of the world and no need of us; thus, we are created completely out of sheer goodness and love (see Catechism of the Catholic Church, art. 1).
Related Articles in the CCC: 199-429

Related Article: "I believe in Jesus Christ, his only Son, our Lord. He was conceived by the Holy Spirit..."
Explanation: Jesus Christ, the Second Person of the Trinity, is Lord over the universe; as the Gospel of John explains, he was present at the creation of the world: "He was in the beginning with God; all things were made through him" (John 1:2-3, RSV). Furthermore, the Second Person of the Trinity took on flesh and became man: "And the Word became flesh and dwelt among us" (John 1:14). God became one of us so that he might redeem us from our sins. By the Holy Spirit, Christ took on flesh in Mary's womb, and thus, he became a servant, taking on death so that we would no longer need to die (see Philippians 2:7-8). When Christ became man, he opened the way to heaven for us.
Related Articles in the CCC: 430-455

Related Article: "...and born of the Virgin Mary."
Explanation: When Christ became man, he chose a specific woman, a daughter of Israel, to be his mother (see CCC 488). Mary was immaculately conceived, meaning that she had no original sin; in this way, God prepared her to become the Mother of God. Mary is the Theotokos--the God-Bearer, for she truly carried the Second Person of the Trinity within her womb. Although Mary became a Mother, she remained a virgin; she is both virgin and Mother. Again, this is a gift from God, for that contradicts the natural order. In Mary, we find a supreme example of faith: when angel Gabriel announced the miraculous pregnancy, Mary says, "Behold, I am the handmaid of the Lord; let it be to me according to your word" (Luke 1:38). Mary assents to the will of God, and in doing so, she becomes the Mother of all the living.
Related Articles in the CCC: 456-511

Related Article: "He suffered under Pontius Pilate, was crucified, died, and was buried. He descended into hell."
Explanation: Christ took on flesh so that he might redeem man from his sin. In the Old Testament, the people of Israel offered up animal sacrifices in atonement for their sins, but these sacrifices were insufficient. Having sinned against an infinite being, man incurred an infinite debt, which he alone could not pay. Thus, God became man, and suffered and died for man, to redeem him from that infinite debt. The death of Christ was therefore necessary for man's salvation. He chose to give everything on the cross because of his great love for mankind (recall that God created the world purely out of love). Thus, Christ shed his blood in the most gruesome form of punishment--crucifixion. He descended into hell, meaning that his body went into hell to bring out those faithful who had died before his coming--Abraham, Jacob, David, and even Adam and Eve.
Related Articles in the CCC: 512-637

Related Article: "On the third day he rose again."
Explanation: When Christ was crucified, his disciples were devastated: most of them, except for John, Mary Magdalene, the Blessed Mother, and some other women who traveled with him, scattered (see Matthew 27:55-56, Mark 15:40-41, and John 19:25-27; Matthew 26:56 and Mark 14:50). They had thought of him as an earthly king, one who would conquer their political enemies. Yet Christ came to save them from their sins, and although he had foretold his resurrection, the disciples could not fully understand. The re-telling of the resurrection in the Gospel of John is poignant: Mary Magdalene went to the tomb early on the third day, and along with Peter, discovered that the stone had been rolled away (see John 20:2). Mary stands weeping outside the tomb, only to be met by Christ himself. Yet she does not recognize him as Christ, but assumes him to be the gardener: "Sir, if you have carried him away, tell me where you have laid him, and I will take him away" (John 20:15). When Jesus says her name, she immediately recognizes him, realizing that he has risen from the dead as he said he would.
Related Articles in the CCC: 638-658

Related Article: "He ascended into heaven, and is seated at the right hand of the Father. He will come to judge the living and the dead."
Explanation: After Mary recognizes Christ, he says to her, "Do not hold me, for I have not yet ascended to the Father; but go to my brethren and say to them, I am ascending to my Father and your Father, to my God and your God" (John 20:17). Christ must ascend into Heaven so that he can send the Holy Spirit to the disciples, who will give them the ability to preach and fulfill the Gospel. As Christ explained earlier in the Gospel of John, "If you love me, you will keep my commandments. And I will ask the Father, and he will give you another Counselor, to be with you forever, even the Spirit of truth" (John 14:15-17). Christ's ascent into Heaven allows the descent of the Holy Spirit at Pentecost, which gives the terrified disciples the strength to preach his Gospel to all nations (see Acts 1:8-9 and Acts 2:1-4; 14-36). Furthermore, because Christ has ascended into Heaven, he will come once again to judge those who are still living and those who have died; he will separate the sheep from the goats, those who have followed his will and those who have not (see Matthew 25:31-46).
Related Articles in the CCC: 659-682

Related Article: "I believe in the Holy Spirit, the holy catholic Church, the communion of the saints, the forgiveness of sins, the resurrection of the body, and the life everlasting. Amen."
Explanation: We shall treat of each of these articles separately. When Christ ascended into Heaven, he sent the Holy Spirit, the Third Person of the Holy Trinity, who proceeds from the Father and the Son in the form of gift. The Holy Spirit is a gift to the Church and sustains the Church through various gifts (see 1 Corinthians 12:4-12). The Church, then, is the Body of Christ here on earth, with Christ as her head in Heaven: "For as in one body we have many members, and all the members do not have the same function, so we, though many, are one body in Christ, and individually members one of another" (Romans 12:4-5; see also: 1 Corinthians 12:27, Ephesians 3:6, Colossians 1:18 and 24). Through the Church, we experience the communion of saints, meaning that we are united with those who have gone before us who have perfectly fulfilled the will of God: as St. Paul says, after listing the holy fathers of the Old Covenant, "we are surrounded by so great a cloud of witnesses" (Hebrews 12:1). The Church allows us to experience the forgiveness of our sins through the sacrament of Penance because of Christ's sacrifice on the cross; it is through the Church that we receive the graces from Christ's death (see CCC 1440-1442). We also believe that, because Christ rose again from the dead, we shall also rise like him, having received the sacrament of baptism and being united to him in the Church: "For if we have been united with him in a death like his, we shall certainly be united with him in a resurrection like his" (Romans 6:5). Moreover, Christ told us that he is preparing a place for us in Heaven; he longs for us to be united with him in eternal life, for this mortal life will pass away (see John 14:3). Thus, we also believe in eternal life: we believe that we will one day be united with Christ in Heaven. That is the whole purpose of this life, to be completely united with Christ in Heaven.
Related Articles in the CCC: 687-1065