At this point, you may be saying, "Okay, but wait a minute - didn't Jesus tell His disciples that not everyone would understand everything? Didn't He Himself say that some things were hidden from those who were not meant to understand them? Doesn't this mean that there are some things we have to dig around and piece together to understand?"
Doesn't this mean there's something to all this so-called gnosticism?
When Jesus talks about things that are hidden from some, He's talking about two very specific groups of persons, neither of whom would be aided by the ideas of gnosticism.
On one hand, He's talking to persons who simply are not yet privy to the Kingdom. He's talking to those who don't really buy into all that He is. He's talking to those who have not been given His Word, even though it has been spoken plainly right in front of them and they have, indeed, heard it.
These are the persons who would just be out to pervert the word. They are the ones to whom none of it makes sense because it's not really what they're looking for at this point in their lives. They're the ones who are curious, but not particularly invested, and this is the kind of person that simply cannot be given the word of God. It doesn't mean anything to them, and so of course some things just don't make sense. Of course some things must be hidden. Even if it were plain as day, they wouldn't know what to do with it, so why bother clarifying what Jesus means in these places?
There's a lot that doesn't make sense about the Gospel unless you know the God who wrote it. There's so much about grace that's counterintuitive, so much about love that seems foolish. There's everything about redemption that doesn't seem necessary unless you first believe in the "very good" and the curse. In these cases, what Jesus is saying when He says that some things are hidden, is basically, "If you don't know My heart, you can't know My word."
On the other hand, He's talking to persons who are captivated by their own god-complex. They are their own idols, and all they are looking for is the chance to boost their own knowledge and power by being privy to the things that Jesus seems to know. You can recognize these moments right away because they usually draw on the idol language of the Old Testament - these persons have eyes, but they do not see; ears, but they do not hear.
Whatever power or knowledge they seem to have, they are figments and products of their own imaginations. And God has not given His Word to make men more powerful in their own minds, to make them more wise in their own ways. He's given His Word to demonstrate His power and wisdom. So when Jesus says these things are hidden from them, what He's saying is that they will never be able to understand them in the figments and fragments of their own imaginations, so they don't actually understand them at all. They are simply misappropriating them, trying to make them something they never were, and so to them, they are nothing at all.
Not once does Jesus say, "These things are hidden, but I have left you enough clues that you should be able to figure them out." No, He always says, "These things are hidden, but I have given them to you." True disciples of Jesus are given the true Word. There's no need to go hunting for it.