In the fourth aliyah Moshe continues to recount the episode of the spies, including the Jewish people's believing the spies' bad report about Israel. Here it says that the children, as opposed to the adults, will eventually inherit the land, and that G-d told the Jews to turn away from Israel, back to the desert, and wander 40 years. Then some Jews realized their mistake, and proceeded to advance toward Israel anyway, but were immediately attacked by the Emorites because G-d was no longer with them.