Why are these Old Testament stories like Amalek written for us?

Les explains that Amalek was a grandson of Esau and that the Amalekites became the continuous enemy of Israel. At this particular time, they came to battle because they saw the abundance of water flowing after Israel smote the rock, so it became warfare over the water God had provided. Les teaches that many of these Old Testament things, as Paul says, are written for our learning, not so much for doctrine, but for practical experience. Just as Israel partook of that living water, when a person comes into right relationship with God, is born again, and becomes a child of God, he partakes of living water. Then the old flesh begins the war against the new nature. The Amalekites picture the flesh warring against the spiritual. At that time Israel was not in grace but still under God dealing with the nation, shortly to be under law.