Before God can entrust us with great things, we must prove faithful with the little things. Yeshua says, "He who is faithful in a very little thing is faithful also in much; and he who is unrighteous in a very little thing is unrighteous also in much" (Luke 16:10). God tested the children of Israel for forty years in the wilderness before bringing them into the Promised Land to humble them and to see if they would remain faithful to His Torah.
"Through many tribulations we must enter the kingdom of God." (Acts 14:22)
During the forty years that the children of Israel wandered in the wilderness, God provided for their every need. He fed them manna from heaven and water from a rock. He miraculously preserved their clothing and shoes so that they would not wear out. Through these daily miracles, the children of Israel learned to trust in God for all their physical needs. They learned that "man does not live by bread alone, but man lives by everything that proceeds out of the mouth of the LORD" (Deuteronomy 8:3).
All of that was about to change. The children of Israel were about to enter the land of promise and enjoy its produce and bounty. They would no longer need to depend on the daily bread from heaven.
God brought Israel through the hardships and trials of the wilderness years in order to train them. "Thus you are to know in your heart that the LORD your God was disciplining you just as a man disciplines his son" (Deuteronomy 8:5), Moses told them.
This can be compared to a wealthy man who bequeathed a large inheritance to his son. However, he knew that if he simply gave the money to his son, the young man would forfeit many important life lessons. So the man put the money into a trust and did not tell his son about it. He let his son get a job, acquire a skill, struggle to raise a family, juggle bills, learn to budget and to handle his resources with thrift. When his son asked for financial assistance, the father would give him only a small sum sufficient for the day. When the father was satisfied that the young man had learned to conduct his affairs responsibly, he gave him the inheritance. He said, "Well done, good and faithful son. You were faithful with a few things; I will put you in charge of many things. Only do not forget the lessons you have learned."
For forty years in the wilderness, Israel learned to rely on God as the source of their provision and sustenance. They were then ready to enter the land of milk and honey. But Moses warned them not to forget the lessons they learned in the wilderness.