One of the hallmarks of the ministry of Jesus of Nazareth is that He spent a great deal of time talking about the Jewish Scriptures. Overwhelmingly, everything He did was steeped in them.
When He takes the scroll in the Temple and begins to read, He reads from the prophecy of Isaiah, and the people are amazed. When He speaks quietly with the disciples, He often quotes the same prophet, referring, of course, to how those prophecies come fulfilled again in Him. When He preaches the Sermon on the Mount, He takes the Scriptures of the law and expands upon them, bringing a fuller meaning into each of God's commands. And we know that He spent a lot of energy engaging with the Pharisees, who were the men who were sure they knew the Scriptures the best. Jesus, of course, continually told them they barely knew the Scriptures at all. (Though we cannot say that was true. The Pharisees knew what the Scriptures said, even when they did not seem to understand the heart of them.)
In fact, regardless of the number of difficulties that Jesus encountered in His ministry, we can say from the testimony of the witnesses that "Scriptural illiteracy" was not one of them. The men and women of the region of Galilee knew their Jewish faith.
It's actually this literacy, this knowledge, that enabled Jesus to do the ministry that He was set on this earth to do. The things that Jesus did, the proclamations that Jesus made, the promises that Jesus fulfilled would have meant nothing at all if the people had not known Him before He came, had not been looking for Him.
Imagine if He'd had to start over every time He wanted to do something.
Imagine if every time Jesus did something Jesus-like, He had to stop and start from the beginning and explain to the crowd why that was Jesus-like. Imagine if He had to keep telling them what it meant that He was doing these things. Imagine if every miraculous, wondrous, wonderful act of Jesus had to come with a statement about which prophecy it fulfilled and why and how. All of a sudden, the Jesus story loses something, doesn't it?
That's not to say that the people understood everything that He did. Not at all. They had plenty of questions, plenty of curiosities. We see it in the whispers that seemed to follow Him everywhere. We see it in the challenges of the Pharisees and those they trained. But because they had a foundation for knowing Jesus, their questions were not really, "What does this mean?" Rather, they were asking, "How is this possible?"
It wasn't that they didn't know; it was that they couldn't believe their eyes.
And this sets up something beautiful for God. He's free to do the things that He's called to do and to just be Jesus, knowing that He doesn't have to tell them who He is; He can show them. And every time He shows them, He takes their breath away again. He draws them a little bit deeper. He becomes even more than they ever imagined He could be. Because He's everything they've hoped for, longed for, waited for, but He's more even than this.
It's how Jesus of Nazareth - can anything good come from Nazareth? - becomes the known presence of the living God - because the people knew their Scriptures so well that they knew what they were looking at, even when they couldn't understand or fathom it.
The whole story of Jesus, it changes if the people don't know what they're looking for. It changes if the people haven't heard the promises. The story of the Son is fundamentally different if the people do not know the Father.
If you don't believe that, just look around.