Jesus, in John 14:1-14, tries to get through to his disciples, and consequently us, that He is God. This concept is one that you hear throughout your Christian life and even sometimes in your non-Christian life. And I think I understand two things now, one Jesus is God, and two, that one thing can be three persons.
Let me explain.
I learned in my psychology class that children go through a certain stage where they can't grasp the idea that one thing can have multiple names. For example, that a cup is also a container, or a plate is also a dish. Adults understand this and use this to categorize the world more precisely. Children just want one name, one thing, they're simpler. I believe this same concept is difficult for adults when it comes to God. God isn't just one thing with many names he's one thing with many persons. For a human to grasp this, is similar for a child to grasp that the color red could also be the color crimson. I'm not analogizing God and Jesus, to red and crimson, I'm saying we don't have the capacity readily available to categorize a thing that is both one thing and many things.
So for Philip to ask in John 14:8 "Lord, show us the Father..." it's not surprising. He can't get this idea that God can be both in heaven and on earth. That he can be both the Father and the Son, simultaneously. In fact He is both. Jesus says it plainly in vs. 9 "Whoever has seen me has seen the Father...I am in the Father and the Father is in me." He's trying his best to put it in words we understand. We need to know this, we need to get this.
Many many people have this deep desire to know God. They may not even know that that is the desire inside them. But it shows up in what they do, how they worship things (give their time and money) and how they have this desire for intimacy. And all this time here he is! He's sitting in plain view, in every bible, in every story of redemption, in every story of sacrifice. God. If they are ever truly want to see God all they have to do is look at Jesus. He is God.