Midrasch zu Schir haSchirim 7:3

(Exod. 30:12:) WHEN YOU TAKE A CENSUS (rosh) OF THE CHILDREN OF ISRAEL…. This text is related (to Cant. 7:3 [2]): YOUR NAVEL IS A ROUND BOWL. LET NOT MIXED WINE BE LACKING. <The verse> is speaking of Israel's Sanhedrin, since it was located in the center of the Temple in the Chamber of Hewn Stones, which resembles a navel.¹Tanh., Exod. 9:2; PR 10:2; Numb. R. 1:4; below, Tanh. (Buber), Numb. 1:4 and Deut. 1:3 with the notes there; Ocf. Sanh. 37a; Exod. R. 39:1; below, Numb. 1:4; also Deut. 1:3. As the navel is located in the middle of the body, so was the Sanhedrin located in the middle of the Temple.

When thou takest the sum of the children of Israel (Exod. 30:12). Scripture states elsewhere in allusion to this verse: Thy navel is like a round goblet, thy belly is like a heap of wheat set about with lilies, wherein no mingled wine is wanting (Song 7:3). Thy navel refers to the Sanhedrin. But why did they call the Sanhedrin a navel? Just as the navel is located in the center of a man’s body, so the Sanhedrin met in a chamber of hewn stone in the center of the Temple. Furthermore, just as the child, whose mouth is closed while within its mother’s womb, is sustained through the navel, so the Israelites were sustained only by virtue of the Sanhedrin. Hence they likened it to a navel. The word round indicates that just as the navel is round, so the Sanhedrin sat in a semicircular room.

(Cant. 7:3 [2], cont.:) YOUR BELLY IS A HEAP OF WHEAT. R. Johanan said: A HEAP OF WHEAT (hittim, sing.: hittah): This is the book of Leviticus, all of which <concerns> sin offerings (hatta'ot, sing.: hatta'ah) and guilt offerings (asamot).⁷Similarly Cant. R. 7:3:2; PR 10:3. It is <the law of> the sin offering (hitta; cf. Lev. 6:18 [25]). It is <the law of> the guilt offering (asham; cf. Lev. 7:1). Moreover, <like the belly in the middle of the body,> it (i.e., Leviticus) is set in the middle of Torah, and all of it <concerns> sin offerings (i.e., the wheat of Cant. 7:3 [2]) and guilt offerings. Ergo (in Cant. 7:3 [2]): YOUR BELLY (i.e., Leviticus) IS A HEAP OF WHEAT (i.e.., sin offerings). Resh Laqish said: Why is it likened to wheat? It is simply that just as all of these wheat grains are reckoned by measure, so all of Israel was reckoned by number (minyan). The elders, the saints, the sages, and all Israel are reckoned by number (minyan).