No, he can choose to reveal himself, but he doesn't have to.
Oh really? Not according to the bible.
If the bible is your instruction manual on the attributes of god, you can compare what it says to reality quite readily.
A few choice quotes:
Mark 11:24, Jesus says, "Whatever you ask for in prayer, believe that you have received it, and it will be yours,"
Matthew 17:20, Jesus says, "For truly, I say to you, if you have faith as a grain of mustard seed, you will say to this mountain, 'Move from here to there,' and it will move; and nothing will be impossible to you."
In Matthew 21:21 Jesus says: "I tell you the truth, if you have faith and do not doubt, not only can you do what was done to the fig tree, but also you can say to this mountain, 'Go, throw yourself into the sea,' and it will be done. If you believe, you will receive whatever you ask for in prayer."
John 14:12-14 Jesus says: "Truly, truly, I say to you, he who believes in me will also do the works that I do; and greater works than these will he do, because I go to the Father. Whatever you ask in my name, I will do it, that the Father may be glorified in the Son; if you ask anything in my name, I will do it."
In James 5:15-16 Jesus says: "And the prayer offered in faith will make the sick person well; the Lord will raise him up. If he has sinned, he will be forgiven. Therefore confess your sins to each other and pray for each other so that you may be healed. The prayer of a righteous man is powerful and effective. "
Mark 9:23 "All things are possible to him who believes. "
Luke 1:37 "For with God nothing will be impossible."
Matthew 18:19 Jesus says: "Again I say to you, if two of you agree on earth about anything they ask, it will be done for them by my Father in heaven. For where two or three are gathered in my name, there am I in the midst of them."
These seem to be pretty darn clear to me and so far, completely false.