"And answering, Jesus said unto him, 'Spiritually prosperous are you, Simon Barjona, because flesh and blood did not reveal this to you but my Father who is in heaven. Moreover, as for myself, I also am saying to you, You are Rock [petros, masculine in gender, a detached but large fragment of rock], and upon this massive rock [petra, feminine in gender, feminine demonstrative pronoun cannot go back to masculine petros; petra, a rocky peak, a massive rock] I will build my church.'" —Matthew 16:17-18
As you can see from the above, taken from Kenneth Wuest's The New Testament: An Expanded Translation, the Roman Catholic Church is in grievous error with regard to its false teachings that Jesus said He would build His church upon Peter, and that Peter was supposedly the first Pope. An examination of the Greek utterly destroys, once and for all time, their ludicrous claims. The name given to Peter is masculine, demonstrating the fact it is referring to Peter. The object Jesus said He would build His church upon would have to be masculine if it were to refer back to Peter (and even then it is not necessarily the case); but it is not—it is feminine. Demonstratively, you could read it, "You are him, and upon her I will build my church." You see the problem here?
Not only was Peter not the first Pope, but he also was not the head of the church or its leader. Jesus is its head. The object upon which Jesus would build His church has nothing whatsoever to do with Peter. It has to do with His confession: "And answering, Simon Peter said, As for you, you are the Christ, the Son of God, the living God'" (v.16). What does Romans 10:9-10 teach us? "If you confess with your mouth Jesus as Lord and believe in your heart that God raised Him from among the dead, you will be saved. For with the heart faith is exercised resulting in righteousness, and with the mouth confession is made resulting in salvation." 1 Corinthians 12:3b informs us that "no person is able to say, 'Jesus is Lord,' except by means of the Holy Spirit."
Jesus' church is built upon that confession: "Jesus is the Messiah. Jesus is the Son of God. Jesus is the living God." With that confession, however, there must be belief that it is true. Otherwise it is just a lip-service confession and the individual is headed to hell on a greased pole. At the consummation of this age, "every tongue [will] plainly and openly agree to the fact that Jesus is Lord, resulting in the glory of God the Father" (Phil. 2:11). Only those who confessed this truth prior to this time will enter the kingdom with eternal life. All others will receive what we all richly deserve—an eternity of physical and conscious torment in hell. And all they will be able to say to God is, "You have done right by me."
If you are a Catholic, get your information right and believe correctly if you do not want to spend eternity in hell being reminded of the errors you believed and followed blindly. If you are a non-believer or a nominal "Christian," repent, believe, and confess the Lord Jesus today before your time runs out and your life is taken from you.