The Torah tell us ויחן שם ישראל נגד ההר that the Jewish people encamped across the mountain and Rashi says כאיש אחד בלב אחד as one person with one heart. This seems to be a very profound idea to discuss before Shavuos as we prepare ourselves to renew our acceptance of the Torah. The question is what is the significance of this idea?
In Parshas Bamidbar the Torah once again records a commandment from Hashem to count the Jewish people. The mefarshim point out that Hashem counts klal yisrael often like a money changer who constantly counts his money. The question is that if Hashem really loves us all, then why does he round off the numbers? A money changer would count every dollar and every cent. It would be inconceivable to believe that every time it just happens to be that the count of the different shevatim just so happens to end with a round number?
Rabbeinu Bachya explains that the Torah wants to reveal an important lesson. Although Hashem cares about every Jew He wanted to instill the idea that what makes the individual significant is how he expands himself to be concerned with the klal. Yes, each individual is special but we are all part of a team and Hashem values us in terms of how we work together and strengthen each other. This is the lesson Hahsem wanted to instill in us by rounding off the numbers.
Based on this we can understand why we recite davening in the plural even though we are davening the personal tefillah of shemonah esrei. This is also why the Arizal writes that one should accept the mitzvah of ואהבת לרעך כמוך before Tefillah and why Rav Ovadya MeBartinura explains the Mishna in Pirkei Avos that states אל תהי רשע בפני עצמך means, one shouldn't be a Rasha and daven without a minyan!
I believe this is the secret that we need to reveal before Shavuos. If we really want to accept the Torah properly we must do so באיש אחד בלב אחד. We can not simply accept the Torah ourselves but rather we must also commit to better strengthen Torah observance in klal yisrael and to love and inspire every Jew to come together and serve Hashem.