Two of the main difficulties encountered in Parshat Devarim are the changes that Moshe makes in his recounting of the incident of the spies that had occurred 40 years previously as reported in Parshat Shlach, and his attributing his inability to enter the Land of Israel to his behavior in the incident of the spies rather than his error of hitting the rock to get water rather than speaking to it, which was the reason given earlier in Parshat Chukat.
In his recounting of the incident of the spies Moshe makes three specific changes: 1) In Parshat Shlach it is clearly stated that G-d instructed Moshe to send spies into the Land of Israel, while here Moshe states that the people came to him requesting the mission. 2) In Parshat Shlach Moshe gave the spies numerous instructions about the nature of the Land, its produce and its inhabitants. Here he only asks them to find the best way to enter the Land. 3) In Parshat Shlach the spies return with a comprehensive report, starting with the positive and ending up with the negative assessment that they would not be able to conquer the Land. Here, however, Moshe only mentions that they said, “Good is the Land that the L-rd our G-d gives us”, which is hardly a negative report!
Moshe made these drastic changes in order to avoid the possibility of a repeat of what had happened 40 years before. If he would mention that G-d and Moshe were the original impetus for the mission of the spies, which ended in disaster, then the people would blame Moshe and G-d for the incident and would therefore lose faith in their ability to conquer the Land. He also ignores specific details about the Land and the spies’ doubts and concerns so as not to plant negative ideas in the peoples’ minds. Instead, he pins the blame squarely on the people of that generation, not this new generation poised to enter the Land. This re-telling of the story is an example of what our Sages teach us in the Talmud (Bava Metzia 87) that it is permitted to change the facts in the interest of peace. In regard to Moshe’s punishment of not being permitted to enter the Land of Israel, it is clear that this punishment is the result of Moshe’s miscalculations with the spies. The additional instructions that he gave them backfired and gave them more ammunition for a negative report. However, since Moshe’s transgression was unintentional, unlike the brazenly false report of the spies, G-d did not want Moshe’s punishment to be mentioned in the same context as the spies’. Additionally, G-d wanted to protect Moshe’s honor and status by not mentioning his punishment in the context of the serious transgression of the spies and the people. In essence He put the decree “on hold” until the incident of the water from the rock, through which the decree was sealed. This is the reason that the incident of the rock is not mentioned in Parshat Devarim at all. That incident alone would never have resulted in such a drastic punishment. The real reason for the decree was Moshe’s role in the incident of the spies.