Question: What are the conditions of entrance into the church?
The word "church" in the New Testament is used, first, of the whole body of believers in Jesus Christ. (Matthew 16;18; Acts 2:47; 20:28; Ephesians 5:24-25; Colossians 1:18, 24). Second, it is used of the body of believers in any one place - for example, the church of the Thessalonians (1 Thessalonians 1:1). Third, it is used of the congregations meeting regularly for worship, teaching, and the breaking of bread - for example, the church that met in Rome in the home of Priscilla and Aquila (Romans 16:3-5).
The conditions of entrance into the church in its first and deepest meaning are acceptance of Jesus Christ as one's personal Saviour, surrender to Him as Lord and Master, and open confession of Him before the world (Romans 10:9-10). the conditions of entrance into local churches are determined by the churches themselves. Most churches receive members upon satisfactory evidence that they have really forsaken sin, accepted Christ as their personal Saviour, and surrendered their lives to Him. Some churches require subscription to a creed, more or less detailed. For example, it might include general affirmations of faith or also more detailed beliefs of the church's denomination. Some evengelical denominations require water baptism on the part of the applicant for membership (See Acts 2:38, 41, 47).
Question: What does Matthew 16:18 mean: "You are Peter, and on this rock I will build My church? Does this verse teach that Peter was the rock upon which Christ would build His church, and does it prove that the Roman Catholic Church, as built upon Peter, is the only true church?
The passage does NOT teach that Peter was the rock upon which Christ would build His church. Peter's name in Greek is "Petros", meaning "a piece of rock." The word translated "rock" in the above verse is "petra", which means "rock." Peter had just made a confession of Jesus as "the Christ, the Son of the living God" (v. 16). Jesus, as the Christ, the Son of the living God, is the Rock upon which the church is built. "No other foundation can anyone lay than that which is laid, which is Jesus Christ" (1 Corinthians 3:11). Peter, by his faith in Jesus as the Christ, the Son of God, and by his confession of Him as such, became a piece of the Rock. Every believer, by believing in Jesus as the Christ, the Son of the living God, and by confessing Him as such, becomes a piece of the Rock and, in this sense, a part of the foundation upon which the church is built, "Jesus Christ Himself being the chief corner stone" (Ephesians 2:20; see also verses 21-22)
Question: Was Peter the first Pope?
No, he was not. There was no pope until long after Peter was dead and buried. The papacy was a later outgrowth of the church of which there was not even an apparent seed in the days of Peter. Peter was far from being a pope. Consider the fact that the apostle Paul rebuked him openly (Galatians 2:11-14).
As I explained in the previous answer, there is no proof that Peter was ever bishop of the church in Rome; there is no decisive proof that he was ever in Rome. However, even if he was, he certainly was not a pope in any sense that the word now carries. There is nothing in the Bible that warrants such an office as that of pope. In fact, Jesus Christ expressly forbids any man from holding such an office. He said in Matthew 23:8-10, "Do not be called "Rabbi"; for One is your Teacher, the Christ, and you are all brethren. Do not call anyone on earth your father; for One is your Father, He who is in heaven. And do not be called teachers; for One is your Teacher, the Christ." Now, the pope claims to be a "father" in the very sense used here, in the very sense that Jesus forbids any man to be called father.
~R. A. Torry~