christ establishes the church:

During his earthly ministry, Jesus Christ established one, holy, catholic, and apostolic Church (Niceno-Constantinopolitan Creed). He said to his apostle Peter, “On this rock, I will build my Church, and the gates of Hades shall not prevail against it” (Matthew 16:18). The Church is therefore a divinely established organization, built by God on a human foundation – divine and human, reflecting Christ himself (CCC 779).

It is one, in that is it undivided in faith, worship, and governance (CCC 815), bound together in perfect love (Colossians 3:14). It is holy, in that it is a people set apart by God for his own glory to be sanctified by him (I Peter 2). It is catholic (from the Greek for according to the whole), in that it possesses the fullness of the means of salvation, led into all truth by the Holy Spirit (John 16:13). It is apostolic because it was founded on the apostles (Ephesians 2:20) and continues to be governed by them and their successors (Acts 2:42).

The Church is the Mystical Body of Christ. “Now you are the body of Christ and individually members of it” (I Corinthians 12:27). By his incarnation, Christ constituted the Church as an extension of his very person, each of the faithful being parts with him as the head. “Christ is the head of the Church, and is himself its Savior” (Ephesians 4:23).

The Church is the Bride of Christ (2 Corinthians 11:2), and by uniting himself to it, he indwells the world and pours out his grace upon it through the Holy Mysteries. “I saw the holy city, new Jerusalem, coming down out of heaven from God, prepared as a bride for her husband; and I heard a great voice from the throne saying, ‘Behold, the dwelling of God is with men. He will dwell with them, and they shall be his people, and God himself will be with them’” (Revelation 21:2-3).

The Church is also a visible institution, subsisting in the Catholic Church and governed by the successors of the apostles (CCC 816) with real authority to judge the faithful and infallibly proclaim the truth. Christ told the apostles “If your brother sins against you, go and tell him his fault, between you and him alone. If he listens to you, you have gained your brother. But if he does not listen, take one or two others along with you, that every word may be confirmed by the evidence of two or three witnesses. If he refuses to listen to them, tell it to the Church; and if he refuses to listen even to the Church, let him be to you as a Gentile and a tax collector. Truly, I say to you, whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven.” (Matthew 18:15-18). The Church cannot err in faith because she is led by the Holy Spirit to be “the pillar and bulwark of the truth” (I Timothy 3:15).

Because Christ established the Church, loved the Church, wed himself to the Church, incorporated her into his mystical body, and entrusted her with the keeping of the means of salvation, Christ cannot be had by anyone apart from her (Pope Francis, General Audience on June 25th, 2024). This is why the holy fathers and the Church herself maintain the ancient aphorism, “Outside the Church there is no salvation” (St. Cyprian of Carthage, Letter LXXII). “All salvation comes from Christ the Head through the Church which is his Body” (CCC 846).