These things I write to you, though I hope to come to you shortly; but if I am delayed, I write so that you may know how you ought to conduct yourself in the house of God, which is the church of the living God, the pillar and ground of the truth. And without controversy great is the mystery of godliness: God was manifested in the flesh, Justified in the Spirit, Seen by angels, Preached among the Gentiles, Believed on in the world, Received up in glory. (1 Timothy 3:14-16)
Paul’s purpose in writing his first letter to Timothy was to give him instructions on how a local assembly and its leadership should function. This verse (1 Timothy 3:15) is commonly cited by Roman Catholics to "prove" the infallibility of the teaching and doctrines of the Roman Catholic Church. The assumption here being that by the process of apostolic succession, the Roman Catholic Church is the church of God and therefore it is "the pillar and ground of truth", which can never error doctrinally.
The bottom-line is that the Roman Catholic Church truly believes that the church did not come from the Bible; the Bible came from the Church and was a written form of what the church had been teaching orally for hundreds of years. In fact, the New Testament is a Catholic document of the faith. It was written by Catholics, vetted by Catholics, and declared inerrant and infallible Scripture by Catholics.
So why does the Roman Catholic Church believe that this verse refers to them? Here are a few of the unbiblical teachings of the Roman Catholic Church: (1) The Catholic Church was the only Church at the time, and Jesus established His Church upon Peter as Prime Minister and thus the only true Church in the fullness of the faith is that church, that group of people, who are loyal and obedient to the successor of St. Peter, the Bishop of Rome, the Pope. (2) This was ordained by God personally and no one has a right to contradict God.
Now let us come back to reality and see what the Word of God says about these passages. Paul is referring to the church as the "pillar and ground of the truth." What he is saying is that we, the church (true believers), are responsible to guard the truth of God's Word. The church is not the SOURCE of truth, as the Roman Catholic Church would have you believe. Rather, it is the DEFENDER of truth already revealed by God.
In 1 Timothy 3:15, when Paul says, "church of the living God", he is referring to the universal (catholic) church that is manifested in local assemblies around the world. Paul goes on to say, "the pillar and ground of the truth" - misconduct and disorder in the local church (true believers) weaken the support of God’s truth in the world. Godly men and women gathering together in local assemblies to worship the Lord produce an orderly church, a church that testifies to others of the truth of God.
The verse, 1 Timothy 3:16, contains an early hymn of the church. Manifested in the flesh refers to Christ’s incarnation, the fact that Jesus became man (see John 1:14). Justified in the Spirit refers to the Holy Spirit’s work in Jesus’ ministry and resurrection (see Matt. 3:15–17; John 16:7, 10; Rom. 1:4; 8:11. ). Seen by angels refers to the angelic witness of Christ’s ministry and resurrection. Preached among the Gentiles refers to the proclamation of Christ to the nations (see Col. 1:23). Believed on in the world refers to the response of individuals to God’s plan of salvation (see 1 Cor. 1:18–25). Received up in glory refers to the Ascension; Christ is seated in God’s presence in heaven (see Acts 1:9; Heb. 1:3, 4).
We can't please God on our own; we must depend on Christ. As a man, Jesus lived a perfect life, and so He is a perfect example of how to live. As God, Jesus gives us the power to do what is right. It is possible to live a godly life - through following Christ.
Is today your day of salvation? Is the Holy Spirit leading you to become a member of God's family by accepting His Son Jesus Christ as your personal Savior and Lord? If you want to know the joy, happiness and peace that a child of God has - please humble yourself right now and ask Jesus to forgive you of your sins and to be your Lord and Savior, King of kings, Lord of lords and Master of your heart, mind and soul. Jesus, I surrender all too you. You are my reason for living. To be obedient to your Lord and Savior, find a body of true believers (church), be baptized, and join them in worshiping our Holy and Almighty God.
References: NKJV Holy Bible, Life Application Bible (NIV), the Nelson Study Bible.