I thought it might be helpful if I shared my faith story. I was born 54 years ago to Catholic parents who baptized me into the Catholic Church a few days after birth. Right before I started school my parents taught me the basic Catholic prayers. Then I started school at the parish school. The good Sisters of Mercy taught me about everything from The Trinity to the Life, Death and Resurrection of Jesus. They also taught me about the Blessed Virgin Mary. They did not back anything up with scripture references. We just believed it because they said so.
Over the years I was confronted by non-Catholics who challenged my beliefs as un-scriptural. I had no answer for them. Then at about age 35 I discovered Catholic Answers. I read the Bible from cover to cover for the first time. I also read several books they recommended as well as internet sites especially Dave Armstrongs website. This was before he took them all down to put them into a couple of books. All these resouces strengthed my faith in all the church’s teachings. I realized though that I was predisposed to believe and these arguments may not be clear enough to change a non-Catholic mind. But I would say at this point that the Bible is not a Catechism. It was not meant to be a systematic exposition of the faith. In the early Church people were not even sure what the inspired writings of the New Testament were. People learned the faith from the Church.No wonder St Paul says the Church is the pillar and bulwark of truth 1 Tim 3:15.
One doctrine I was sure of just through scripture was the Eucharist. After studying John 6 and the various accounts of the Last supper I had no doubt that the Eucharist we receive at Mass is the Body, Blood, Soul, and Divinity of Christ. Since the Catholic Church is the only Christian Church to believe this I knew the Catholic Church was the one mentioned in 1 Tim 3:15