There is a certain feeling when you are in the C class for maths, and you have to sit through the ceremony for students from the A group who have finished their exams with distinction! This is the feeling we have when we read a midrash that answers an important question in our parsha.
After the Torah tells us about the order the movement of camps , there us a new seemingly unconnected subject:
צַו אֶת בְּנֵי יִשְׂרָאֵל וִישַׁלְּחוּ מִן הַמַּחֲנֶה כָּל צָרוּעַ וְכָל זָב וְכֹל טָמֵא לָנָפֶשׁ מִזָּכָר עַד נְקֵבָה תְּשַׁלֵּחוּ אֶל מִחוּץ לַמַּחֲנֶה תְּשַׁלְּחוּם וְלֹא יְטַמְּאוּ אֶת מַחֲנֵיהֶם אֲשֶׁר אֲנִי שֹׁכֵן בְּתוֹכָם
Speak to the children of Israel that may send away any leper, or inpure person ,male or female, from the camp, in order that they will not make the camp I dwell in impure