The construction of the Mishkan is described in Exodus 26 with a catalog of measurements and materials that reads, on the surface, like an architect's invoice. Ten curtains of fine linen, coupled five and five. The Torah devotes entire chapters to joinery and loops.
The Targum Pseudo-Jonathan on Exodus 26:9 refuses to leave the numbers inert. When the text says thou shalt conjoin five curtains together, the Targum adds the interpretation: corresponding with the five books of the Law. The second set of six curtains, the Targum says, corresponds with the six orders of the Mishna. The whole tabernacle becomes a map of the Torah, written and oral.
This is a daring reading. The Mishnah, compiled by Rabbi Yehudah HaNasi around 220 CE, did not yet exist when the Mishkan was pitched in the wilderness. But the Targum argues that its six orders, Zeraim, Moed, Nashim, Nezikin, Kodashim, and Taharot, were already woven into the roof over the Holy of Holies. Written Torah and Oral Torah were not merely given at Sinai. They were stitched into the fabric that sheltered the Ark.
The theological claim is clear. You cannot have the Mishkan with only five curtains. The sixth set, folded at the front, hangs where Israel enters. Oral Torah faces the people. Written Torah covers the inner sanctuary. Both are needed, and neither is complete without the other.
The takeaway applies to every beit midrash since. A Jewish sanctuary is a room where Written and Oral Torah meet. Pull one curtain away, and the roof collapses.