On the road to rescuing Princess Fiona, Shrek tries to explain to Donkey the complexities of ogre personality. "Ogres are like onions," he says. "They have layers."
Scripture is like ogres...I mean onions. It has layers. What does this mean? One of the primary characteristics of Scripture, is, being inspired by God, it has meaning when it was revealed, relating to the time and place to which it is tied. Scripture also has meaning throughout time, off times in relationship to salvation history, that is, to the story of our salvation through Christ. It also speaks to us today, in our own lives. One thing this means is that trying to tie a single definitive meaning to a specific scriptural passage is a chancy thing. Almost all passages of scripture have more than one authentic meaning, as well as an almost unlimited number of incorrect interpretations, hence the danger of solo scriptura and the need for the Magisterium of the Church.
One place where scripture is very much part of our daily lives is during the Mass. Scott Hahn does a very good job of explaining how The Book of Revelations is a map to the Mass, as well a probable writing on the first century Roman Empire, as well as a possible hint of the end times. See, like an onion?
One place that scripture is very visibly in the Mass is during the readings. When the Mass was revised after Vatican II the cycle of readings was changed from a single year cycle, which is still used in the Extraordinary Form of the Roman Rite, to a three year cycle. Readings were added and an attempt was made to try together at least two of the readings. This most often results in a common thread running between the first reading, which is most often from the Old Testament and the Gospel.
For the Twenty-first Sunday of Ordinary time, cycle II (or B) we hear from Isaiah 22:19-23. The story concerns Shebna, who was the steward of Hezekiah, King of Judah, that is the Southern Kingdom of Israel. In those days the king's steward was the government comptroller, secretary of the treasury, head butler and chief of staff all rolled into one. The crux of his duties and the source of his power was that he held the keys of the king. When it was time to pay people he had the keys to the treasury. When someone wanted to see the monarch he held to keys to the door they would have to pass through before they could enter the king's presence. The king held the real power, but folks understood that the steward held authority too. That authority came from the king, but like the power of the king that authority ultimately came from God. Shebna was reminded of this fact when God sent Isaiah to toss him out of office and anoint Eliakim to take his place.
Now the Gospel comes from Matthew 16:13-20. This is one of the readings that Protestants dance around and write whole books about how Catholics have got it wrong. This is the place where Christ gives the Keys of Kingdom to Peter. Like Eliakim he will be able to open or close doors and from that will flow his power to bind and loose, a term that in Jewish law was concerned with the ability of rabbis and judges to interpret law and contracts. Like Eliakim his power does not come from his own authority, but from the authority of the King. In Israel the position of steward was hereditary with the power of the keys being passed down to the Eliakim's heirs.
Now it was a sure bet that the Apostles knew the story of Eliakim. They would have recognized the meaning of Christs words, when he used the terms "keys", "binding" and "loosing." Even after Jesus' death, before Pentecost, they, the Apostles, gathered around Peter and recognized his authority. Which is why Mary Magdalene sought him out when told to tell the Apostles about her meeting with the Lord following his resurrection. And why the other Apostle, even though he reached the tomb first on Easter morning, allowed Peter to enter first, out of respect to his position as leader of the Apostles. Even Paul, who was appointed an Apostle by Jesus himself, sought out Peter to bless his ministry.
Often you'll hear a Protestant apologist claim that the early Church fathers don't mention the primacy of the Bishop of Rome. They don't mention the existence of the Emperor either, or the geographic location of Rome or the color of the sky. Why not? Because those were assumptions that they knew were accepted by their readers already. One does not explain or defend that which is already accepted.