This is an excellent question, Michael, and I don’t know the answer – but I’ll muse a bit and maybe find something good . . .
Faith is the substance of things hoped for and the evidence of things not seen. So is faith maybe in some measure a window for us into the spiritual world? Without faith, it’s impossible to please God, for he who comes to God must believe that He is, and that He is the rewarder of those who diligently seek Him. It makes sense to me that the reward for the seeker would be to find the thing/person sought.
“This is the work of God, that you believe on Him whom He has sent” (Jesus). Jesus is “the true bread who came down from heaven that a man may eat thereof and not die.” “For my flesh is meat indeed and My blood is drink indeed. The one who eats My flesh and drinks My blood has eternal life and I will raise him up on the last day.” (All in John 6, somewhere.)
Back in the Garden there was the Tree of Life, free to be chosen. We could have eaten from it, but we didn’t. Why? It symbolizes Jesus, I think. If you eat of it, you will have eternal life (the sort of life that comes from the Eternal – God) And knowing God IS eternal life. If you eat from the TOL, you’ll know God. And knowing God, you’ll have the mind of Christ and know all things (perhaps not at once, but as you need them). But why eat from the TOKOGE, then ? You will be as God (they were already like God) and know good and evil (for ourselves? without knowing through that interface with God, in our spirits? independently know? is that what appealed?)
Things not seen – that sounds like the spiritual world which we, having died to that world on eating from the TOKOGE, cannot see or sense. But when we eat from the TOL, we begin to live again to the spiritual world – God’s world. But it’s a seed. The Kingdom of God is like a seed, and it has to be planted in good ground. And a seed has to fall into the earth and die before it can grow and bear fruit.
Jesus is the Word, and He did “fall into the earth and die.” But the fruit of a seed is more seeds, which, in order to live must also first die. He will see His seed; He will prolong His days, and the pleasure of the Lord will prosper in His hand. Are we His seed? Things don’t ALWAYS symbolize the same thing. However I think maybe in this case, maybe we are. And if we are His seed, we must die to this world as He did. And that means we need to learn to live that God kind of life (eternal life).
Jesus’ disciples asked Him something about how to do the things He did (I think it was the fig tree incident) and He said “Have faith in God.” But I’ve heard that maybe that would be better translated differently – as “Have the faith OF God.” Have the sort of faith God has – the God kind of life and the God kind of faith. Is this faith somehow connected to eating from the TOL as opposed to the TOKOGE? Taking into ourselves (I hate to put it the way Jesus did, you know?) the Son of God?
So the faith is necessary to please God because that’s His goal for us – to learn to live by His life, to discern things (more and more) in the spirit realm, to have His kind of faith, KNOWING the spirit realm, knowing the power He’s invested in us (greater works than these shall you do because I go to My Father).
As for His not manifesting Himself to us all the time, I have a kind of picture of that which I like. You know how adults and older children will play peek-a-boo with the baby? It’s so delightful to see Silas’ little baby face giggle and gurgle when you uncover your face or pop back in from behind the cushion or even the next room. But the game has a serious side. Silas doesn’t know that you still exist if he can’t see you. He has to learn this, because he’s not always going to see you. Besides, it’s just a fact of existence which he should know for the sake of knowing. There are things in the world besides himself, and they exist whether or not he can see or touch them at the moment. It’s part of growing up.
I wonder if that’s part of God trying/testing our faith. It’s not so much to see whether we’ll stand strong. He knows He’ll pick us up if we need it. It’s more playing peek-a-boo. We need to know that He’s there and that He’s good even if we can’t see Him at the moment. We need to have that God kind of faith and live by that God kind of life – not merely by our senses. Besides, this world of material things is good, but it isn’t all there is. And maybe it’s not the best interface in which to interact with Him.
We need to learn to live in a whole new world in which we have (like baby Silas) very limited functionality at present. I believe that physical world (redeemed) is very good and will always be part of our lives, but there’s more, and we need to learn to swim or fly or whatever analogy you like, in the spirit world now. So maybe the testing/trying is to help us learn? To strengthen our spirit “muscles,” as a baby strengthens his legs as he learns to pull himself up, and then finally begins to take his first steps.
Sight is the currency of this world. Sure, there are other senses, but sight is pretty much king, if you’ve got it. Perhaps faith is the “sight” of the spirit world. God’s testing our faith is like your testing your little girl’s ability to keep her bicycle upright by letting go of the handlebars as you run alongside. Just kind of stream-of-consciousness. Thanks for the nudge, Brother. 
