Bemidbar 

במדבר

The positioning of all the tribes in the framework of the different camps is similar to the configuration of the administering angels, which are also identifiable in their places and in their unique camps. 

When the Holy One, Blessed be He, revealed Himself on Mount Sinai, 22,000 chariots of angels descended with Him, as it is stated: “The chariots of God are myriads, thousands upon thousands of companies” (Psalms 68:18),<footnote data-num="4"/> and they were all divided into camps [degalim], as it is stated: “My beloved is clear and ruddy, more eminent [dagul] than a myriad” (Song of Songs 5:10). Once the Israelites saw that the angels were divided into camps, they began desiring camps of their own. They said: If only we could divide into camps like them…. If only He will bestow love upon us…. The Holy One, Blessed be He, said: What did you desire, to be divided into camps? By your lives, I will fulfill your wishes…. Immediately, the Holy One, Blessed be He, pronounced His love for Israel and said to Moses: Go divide them into camps as they desired. <source>(Bemidbar Rabba 2) </source>