Normally when Moshe spoke to the people he would address the leaders and then the people. However, here he addresses the nation as a whole. אתם ניצבים היום כולכם לפני ה, "You are standing today, all of you before Hashem." The Alshich explains when we are all standing together before Hashem, everyone is equal. When we are before Hashem, Who knows everyone's true worth, there is no hiding behind titles or appearance. Only then are we all equal. No human being really knows the importance of anyone else for the way we measure and the way Hashem measures are totally different. The most prestigious person in our eyes can be less worthy in Hashem's eyes than the simplest person in our eyes for we cannot know a person's true worth.
Rav Simcha Bunim of Pshischa proves this from a halacha. The Torah tells us that one who is threatened with death unless he kills someone else has to allow himself to be killed, as the Gemara explains, “Who says your blood is redder (more valuable), perhaps your friends blood is redder." Thus, if the leading Torah sage can save his life only by killing the most ignorant Jew, he must let himself be killed. Prestige and importance cannot always be counted as true greatness for we cannot know who is really more important to Hashem. The otzer hatorah explains with a story. A wealthy diamond merchant who was a follower of the Rashab of Lubavitch asked the Rebbi why he honored simple jews. The Rebbi responded because they have many positive qualities to them. To which the chassid replied, I don't see them. Later the Rebbi asked him if he brought his pouch of diamonds with him. Of course, he said. He opened the pouch and showed the Rebbi the stone and said, "Look, this one is dazzling." The Rebbi said, "I don't see anything special about it." "Rebbe," said the chassid, "excuse me for saying this but to really appreciate a diamond you have to be an expert." "Yes," retorted the Rebbi. "A Jew, any Jew is more brilliant and dazzling than the most precious jewel. But to perceive the beauty of a Jew one also needs to be an expert."
The next parsha we read this week has the mitzvah of הקהל, where everyone has to come, men women and children, to listen to the king read the Torah. The Gemara asks, I understand why the men have come and I understand why the woman have to come, but the children, why do they need to be there? The Gemara answers to bring reward to those that bring them. The chedushai harim asks, why is the Gemara asking why the kids have to come? If the mothers are coming and the fathers are coming, who's going to watch the kids? Of course they have to come! He answers that the Gemara is really asking why you even have to mention to bring the kids if they are obviously coming. He answers it is to give us reward, for the reward is much greater for one who is commanded to do something and they do it, then doing it just because, without a command.
Perhaps another reason is to reiterate the lesson that we don't know anyone's true value. Men, women and children all going to the same class, everyone being taught the same thing all together, from the greatest rabbi to the smallest child, shows Hashem that we are all together. As we approach Rosh Hashana and are going to be asking for Hashem to remember us and want Him to think that we're special, it's important to remember that every person is special and for us to treat each person like they are the most prestigious person. If we do this, all the more so Hashem will treat us that way and we will all merit a great new year!