If we wish to locate the Church founded by Jesus, we need to locate the one that has the four chief marks or qualities of his Church. The Church we seek must be one, holy, catholic, and apostolic.
The Church Is One (Rom. 12:5, 1 Cor. 10:17, 12:13, CCC 813–822)
Jesus established only one Church, not a collection of differing churches (Lutheran, Baptist, Anglican, and so on). The Bible says the Church is the bride of Christ (Eph. 5:23–32). Jesus can have but one spouse, and his spouse is the Catholic Church.
His Church also teaches just one set of doctrines, which must be the same as those taught by the apostles (Jude 3). This is the unity of belief to which Scripture calls us (Phil. 1:27, 2:2).
Although some Catholics dissent from officially-taught doctrines, the Church’s official teachers—the pope and the bishops united with him—have never changed any doctrine. Over the centuries, as doctrines are examined more fully, the Church comes to understand them more deeply (John 16:12–13), but it never understands them to mean the opposite of what they once meant.
The Church Is Holy (Eph. 5:25–27, Rev. 19:7–8, CCC 823–829)
By his grace Jesus makes the Church holy, just as he is holy. This doesn’t mean that each member is always holy. Jesus said there would be both good and bad members in the Church (John 6:70), and not all the members would go to heaven (Matt. 7:21–23).
But the Church itself is holy because it is the source of holiness and is the guardian of the special means of grace Jesus established, the sacraments (cf. Eph. 5:26).
The Church Is Catholic (Matt. 28:19–20, Rev. 5:9–10, CCC 830–856)
Jesus’ Church is called catholic ("universal" in Greek) because it is his gift to all people. He told his apostles to go throughout the world and make disciples of "all nations" (Matt. 28:19–20).
For 2,000 years the Catholic Church has carried out this mission, preaching the good news that Christ died for all men and that he wants all of us to be members of his universal family (Gal. 3:28).
Nowadays the Catholic Church is found in every country of the world and is still sending out missionaries to "make disciples of all nations" (Matt. 28:19).
The Church Jesus established was known by its most common title, "the Catholic Church," at least as early as the year 107, when Ignatius of Antioch used that title to describe the one Church Jesus founded. The title apparently was old in Ignatius’s time, which means it probably went all the way back to the time of the apostles.
The Church Is Apostolic (Eph. 2:19–20, CCC 857–865)
The Church Jesus founded is apostolic because he appointed the apostles to be the first leaders of the Church, and their successors were to be its future leaders. The apostles were the first bishops, and, since the first century, there has been an unbroken line of Catholic bishops faithfully handing on what the apostles taught the first Christians in Scripture and oral Tradition (2 Tim. 2:2).
These beliefs include the bodily Resurrection of Jesus, the Real Presence of Jesus in the Eucharist, the sacrificial nature of the Mass, the forgiveness of sins through a priest, baptismal regeneration, the existence of purgatory, Mary’s special role, and much more —even the doctrine of apostolic succession itself.
Early Christian writings prove the first Christians were thoroughly Catholic in belief and practice and looked to the successors of the apostles as their leaders. What these first Christians believed is still believed by the Catholic Church. No other Church can make that claim.
there has been an unbroken line of Catholic bishops faithfully handing on what the apostles taught the first Christians in Scripture and oral Tradition (2 Tim. 2:2).
Some Christians claim, "The Bible is all I need," but this notion is not taught in the Bible itself. In fact, the Bible teaches the contrary idea (2 Pet. 1:20–21, 3:15–16). The "Bible alone" theory was not believed by anyone in the early Church. Although popular with many "Bible Christian" churches, the "Bible alone" theory simply does not work in practice. Historical experience disproves it. Each year we see additional splintering among "Bible-believing" religions. We know this for sure: The Holy Spirit cannot be the author of this confusion (1 Cor. 14:33). God cannot lead people to contradictory beliefs because his truth is one. The conclusion? The "Bible alone" theory must be false.
Together the pope and the bishops form the teaching authority of the Church, which is called the magisterium (from the Latin for "teacher"). The magisterium, guided and protected from error by the Holy Spirit, gives us certainty in matters of doctrine. The Church is the custodian of the Bible and faithfully and accurately proclaims its message, a task which God has empowered it to do. Keep in mind that the Church came before the New Testament, not the New Testament before the Church. Divinely-inspired members of the Church wrote the books of the New Testament, just as divinely-inspired writers had written the Old Testament, and the Church is guided by the Holy Spirit to guard and interpret the entire Bible, both Old and New Testaments. The magisterium is infallible when it teaches officially because Jesus promised to send the Holy Spirit to guide the apostles and their successors "into all truth" (John 16:12–13).
Over the last few decades many Catholics have left the Church, many dropping out of religion entirely, many joining other churches. But the traffic has not been in only one direction.
The traffic toward Rome has increased rapidly. Today we are seeing more than a hundred and fifty thousand converts enter the Catholic Church each year in the United States, and in some other places, like the continent of Africa, there are more than a million converts to the Catholic faith each year. People of no religion, lapsed or inactive Catholics, and members of other Christian churches are "coming home to Rome."
Only the Catholic Church was founded by Jesus, and only it has been able to preserve all Christian truth without any error—and great numbers of people are coming to see this.
EWTN is a cable station that hosts a program entitled: The Journey Home. It airs Monday nights at 8-pm EST (check local cable listing for the channel). This program may well answer many of your questions. You can email the host, Marcus Grodi or call in with your questions - the program is normally live.
Alternatively, you can visit the web site set up by Marcus Grodi and explore its forum. There you can post your questions and trust that they will be responded to by qualified individuals. I am not an apologist, simply a soul on a personal journey 'home'. May the Holy Spirit continue to guide and direct you along your path.