That's the point in Christianity, to put your faith in God to earn His grace, to believe in His words, to be led by Him into kingdom of Heavens. We dont need to know what God is, but who God is. Creator of everything. We as a failed creation could have been wiped clean as defected product long time ago, like people in the flood were. Yet God decided to give us a chance to accept the salvation.
I dont understand people, they blame God for the world being evil and full of suffering, yet they are the one doing the evil and hurting the others causing that suffering when given the chance. If people obeyed every commandment and word given by God, world would be a perfect place. They want others to be forced by God to be good, but would never accept being a puppet controlled by God themselves giving up all the evil stuff, main character syndrome. In God's eyes we are all at fault and sinful.
He was wrong though. Bible never said that there are rewards and punishments (sins get forgiven, and people who gain Gods favor for spreading His word are not promised a good life, they are saved anyway and will get reward in Heaven. If they are not saved, no reward for them in heaven no matter what they did) and that being good leads you to Heaven. For salvation very few things matter, by faith in God believing that he died on a cross for our salvation and accepting him as a Saviour we gain His grace to be saved. Thats it. Once you are saved, your sins wont condemn you to hell. Salvation is earned by faith, not by work. Someone can do all good in his whole life and still go to the hell, and other can sin whole his life and still go to the heaven. Jesus condemned the Pharisees the "righteous" people who believed their work (following the laws of Moses) is their salvation even though they had no love for God in themselves.
The criminals on the cross with Jesus are good example. Both were sinful murderers, who knows what were their crimes because crucifixion was a capital punishments for crimes so serious that had to be judged by Romans. One mocked and tested Jesus, demanding to prove himself a God by saving them. The other accepted Jesus as the God, admitted being a sinner and asked Jesus for salvation. First one ended up in hell, the second went to heaven. Both died the same way. They are the perfect picture of an atheist and an christian.