There are many lessons to be learned from reading Holy Scripture, but in my opinion, one of the most important lessons to be learned is that we humans should learn to totally trust in God to do what's best for us, at all times, no matter how bleak the situation is. Of course, the caveat that goes with that is that we should be obeying His Holy Word as well.
Let's take a look at a few examples from the Old Testament.
God told Abraham that his descendants would be as numerous as the stars in the sky, and yet here he was approaching 100 years old, with a wife Sarah who was 90 years old. So what did Abraham and Sarah decide to do on their own? Well, Sarah told Abraham to have sexual relations with her slave girl Hagar. Abraham agreed, and Ishmael was born. But Ishmael was not to be the heir that God promised. Hagar started to make fun of her boss Sarah when Ishmael was seen with Abraham, so Sarah told Abraham to get rid of them both. They were sent out into the desert, but God took care of them there. The descendants of Ishmael eventually became the followers of Mohammed. God eventually appeared to Abraham and Sarah, and told them that in the next year Sarah would conceive a natural son of Abraham, even at their advanced age. Because Abraham didn't truly trust in God, as evidenced by his relations with Hagar, God put him to the test once Isaac got older. God told Abraham to go up Mount Moriah and sacrifice Isaac in a holocaust. Abraham agreed to do this, even though he knew that he would be killing of his only male heir, which would seemingly negate God's promise to make his descendants as numerous as the stars in the sky. As Abraham was about to plunge the dagger into his son, an angel of the Lord stopped him, because God now could see that Abraham TOTALLY trusted in God, even though he couldn't understand God's plan.
After the golden calf incident, the Israelites were told by God to go invade the land of the Canaanites and kick them out (Numbers 13-14). The Israelites had already seen the power of God, who divided the Red Sea for them to escape from Pharaoh's army. They knew that God was on their side, and that He would protect them. Moses sent spies into the land of the Canaanites to get the lay of the land. When they came back after 40 days with a large supply of the fruit of the promised land, a majority of the spies said that the Canaanites were too big and strong, and it would be best if they DIDN'T go to war with them. Only two spies, Caleb and Joshua, said that they could take down the Canaanites, because of God's protection. All of the other Israelites who heard the report agreed with it, and started to rebel against Moses for bringing them out of Egypt. As a result of their disobedience and lack of trust in Him, God swore that only the children of the current generation would ever see the promised land, along with Moses, Caleb, and Joshua. They would now have to wander in the desert for 40 years, one year for each day that the spies were in the land of Canaan. And so the penalty for not trusting in God to defeat the Canaanites was a slow painful trek in the desert for 40 years, and none of the grumblers ever got to see the land flowing with milk and honey, as they died in the desert as a penalty for NOT trusting in God to protect them from the Canaanites.
So how can we apply these lessons to our lives today? We should always know that God is our loving Father, and that if we TOTALLY trust in Him to take care of us no matter what the situation, are obeying the Commandments, AND are trying our best to live out the Christian message with our thoughts, words, and deeds, then we have a spiritual hedge of protection around us. This hedge can only be taken down by our sinful actions, which say that we prefer the ways of the devil to the ways of God. This was true in the Old Testament, and it is certainly true today for us, who now wander through the very dry and hazardous desert known as secular America.
Another lesson learned is that God will always allow satan to test us throughout our lives, to see if we REALLY love God and obey his Holy Word, or if we are just giving him lip service. Like the Israelites in the desert and like Abraham, our DEEDS speak a lot louder than our words!
"I tell you that you have less to suffer in following the cross than in serving the world and its pleasures." -- St. John Vianney