NAB2 MAT 23:2
Then Jesus spoke to the crowds and to his disciples, saying, The scribes and the Pharisees have taken their seat on the chair of Moses. Therefore, do and observe all things whatsoever they tell you, but do not follow their example. For they preach but they do not practice.
I am Catholic because Jesus wills me, as well as all His followers, to be Catholic. Jesus tells us how evil the Pharisees who sit in Moses Seat are. Then Jesus tells us that we must respect God's authority in them. Untill Jesus Himself tells the world to follow someone else as the leader of His Church, then the Leaders of Christ's Church, are the Catholic Church.
We also have the Sacraments which Christ gave to His Church.
NAB MAT 16:13 Peter the Rock.
When Jesus came to the neighborhood of Ceasarea Philippi, he asked his disciples this question: "Who do people say that the Son of Man is? They replied, "Some say John the Baptizer, others Elijah, still others Jeremiah or one of the prophets." "And you," he said to them, "who do you say that I am?" "You are the Messiah," Simon Peter answered, "the Son of the living God!" Jesus replied, "Blest are you, Simon son of John! No mere man has revealed this to you, but my heavenly Father. I for my part declare to you, you are 'Rock', and on this rock I will build my church, and the jaws of death shall not prevail against it. I will entrust to you the keys of the kingdom of heaven. Whatever you declare bound on earth shall be bound in heaven; whatever you declare loosed on earth shall be loosed in heaven." Then He strictly ordered his disciples not to tell anyone that he was the Messiah.