A not very original thought about the Old Testament

Have you ever wondered why God has treated His people differently throughout the ages? I mean, He does not deal with us in the exact same way He used to. Now, I'm sure there have been many theories and reasoning's presented, many by men far smarter and wiser then I. The reason this is coming up is that I've been reading a blog. You see, there is this man, David Plotz, who earlier this year finished reading through the Bible. Now, David, a nominal Jew, had never read through the entire Old Testament. As he read, he blogged. Somethings delighted him; he found the imagery fascinating and some of the advice profound and changing. Other findings horrified him. He found God in the Bible to be "awful, cruel, and capricious" (http://www.slate.com/id/2212616/pagenum/2). This was not the God he was looking for. I know I also sometimes have wondered why God has treated people differently throughout the ages. Now, I do not claim to know the mind of God, but I do have a theory. What if part of the reason is to show that His way of salvation is best?

What I mean is, what if it's sort of a giant object lesson. Proof for us that there really is only one way to Him (through Jesus Christ on the cross). You see, if we did not have the Israelite wanderings, people might question God's methods. Not that they don't, but by doing what He did with them He proved that Miracles and personally showing His power will not automatically save anyone. You see, people might go "well, if God just proved that He was powerful" or "If He just showed how much sin displeased Him" or "If he just worked one more miracle." No matter how much God did, it was never enough. The Israelites in the OT always turned their back on Him. No matter what God did, mankind ALWAYS rebelled. If He gave mercy, they rebelled; If He punished sin harshly, they rebelled. Whether He promised Judgment (the majority of the prophets) or spoke tenderly (Hosea 11) they were never faithful for long. The OT is in many ways a giant testimony to the Failure of Man and his own inability to earn salvation. Even the best and blessed ultimately fail (David, Samson, etc.). Is it any wonder that God sent His Son to die for us (John 3:16)?

I am not saying that God didn't know what He was doing (Gen 3:15 shows He did know what would happen from the very beginning) but in a way the OT is a one large essay by God. His proof and His way of saying "See, you can't do it on your own!"