The beginning of Parashat BeMidbar deals with the census of Bnei Yisrael and the formation the Shevatim took in their travels and encampments. The first Pasuk of the Parasha tells us that Hashem spoke to Moshe on the first day of Iyar in the second year after Bnei Yisrael left Mitzrayim. While discussing where each set of Shevatim would encamp, the Torah states, "Ish Al Diglo" "Each man by his flag" (BeMidbar 2:2). It would seem that before this, each Jew could live wherever he wanted inside the camp. Why did Hashem wait so long to command Bnei Yisrael to arrange the Shevatim by flags?
Rav Chaim Kanievsky suggests that the flags introduced "separation" into the camp of Bnei Yisrael. Each Sheivet's flag had a distinct color and represented a special quality or trait that Sheivet possessed which made it distinct from all the other Shevatim. Therefore, before the Mishkan was built, to arrange the camps by flags was dangerous; these separations would have created jealousy and competition among Bnei Yisrael. After the Mishkan was built, however, this worry did not exist. All Bnei Yisrael camped around the Mishkan and each Jew saw what was central to his life. Now, each Sheivet had the Shechinah resting in close proximity to it. Bnei Yisrael learned that their feelings of jealousy were inappropriate. The camps surrounded the Mishkan as one cohesive unit, with each Sheivet serving a different role. Each Sheivet worked with the others to maintain the completeness of the Machanot. Hashem, therefore, instructed Bnei Yisrael about the camps and Degalim only after the Mishkan was built.
Not every Jew takes the same path in his Avodat Hashem. Sometimes, these differences can create strife and enmity and lead to terrible disputes. The way to avoid these destructive arguments is to focus not on the details of differing observance, but rather on the central goal of serving Hashem which all share.