According to tradition, the Israelites refused to enter the land on the ninth day of the fifth month (Tisha b'Av). Consequently, Judaism observes that day as an annual fast day. The same date is the anniversary of the destruction of both the first and second Temples:
On the ninth of Av it was decreed that our fathers should not enter the land, the Temple was destroyed the first time, and the second time. (b.Taanit 29a)
The first Torah reading from the book of Deuteronomy is always read on the Shabbat before the ninth day of the fifth month.
In this week's Torah portion, Moses retold the story of sending the twelve spies into the land of Canaan and the tragic results of that mission. He reminded the generation of how their fathers faithlessly refused to enter the land and how God punished them with the wandering in the wilderness. He retold the story of how, after the rebellion, the Israelites made a failed attempt to enter the land.
You have probably heard the expression "Two wrongs don't make a right." This means that when we have done something wrong, we should not try to correct the error by doing another wrong. After committing the sin of rejecting the land, the Israelites perceived that they had displeased the LORD. They reversed themselves and immediately prepared to enter the land. They girded themselves for war to attempt an invasion. The LORD spoke through Moses, telling them, "Do not go up nor fight, for I am not among you; otherwise you will be defeated before your enemies" (Deuteronomy 1:42).
The Israelites would not listen. They attempted an invasion of Canaan and were soundly beaten back. When God told them to enter the land, they would not. When God told them not to enter the land, they insisted on entering.
Ordinarily, repentance is a simple matter. When we realize we have sinned by doing something wrong, we simply need to confess our wrongdoing, turn around and do the opposite. However, it is not always so simple. Sometimes our sin creates consequences that make it impossible for us to reverse course.
For example, suppose a father forbids his daughter from a certain marriage. She refuses to listen and elopes with the fellow. After a year of marriage, she realizes that she has made a terrible mistake by ignoring her father's warnings. She decides to end the marriage. After all, her father didn't want her to be married to this man. The second wrong does not right the first wrong. The choices we make have consequences, and sometimes it is necessary to live with those consequences.
Spiritual maturity requires us to accept the consequences of our actions. The children of Israel were not willing to accept the consequence of their rejection of the land. Rather than submit to the forty-year decree, they rebelled against God's word again. When we truly trust God, we will be willing to submit to His justice, even if it means discipline.