In the first aliyah, we find the Jewish people a mere three days away from their entry to the promised land, and as Rashi says, the Jews went to Moshe and asked if they could send spies to check out the land they were going to.

Moshe tells them there is no need for this because G-d promised them a good land. But G-d gives them free will to err this way, and in this aliyah G-d gives permission for the Jews to send spies to spy out the land. Rashi points out that this section is right next to the section in the previous parsha about Miriam's loshen hora and her punishment, to give the spies an opportunity to learn from her.

Due to their actions in this parsha the Jewish people will have to wander in the desert for 40 years before reaching the land of Israel.