Mary Douglas, (Leviticus as Literature, 59–64) made this observation long ago:
“Both Sinai and the Tabernacle evidence a tripartite division. The summit corresponds to the inner sanctum, or Holy of Holies. The second zone, partway up the mountain, is the equivalent of the Tabernacle’s outer sanctum, or Holy Place. The third zone, at the foot of the mountain, is analogous to the outer court. As with the Tabernacle, the three distinct zones of Sinai feature three gradations of holiness in descending order. Just as Moses alone may ascend to the peak of the mountain, so all but one are barred from the Holy of Holies in the Tabernacle” (59).
Likewise, Larsson writes,
“Just as here at Sinai, there came to be an area to which all of Israel had access, another reserved for the priests, and finally an inner ‘holy of holies’ into which only the high priest could enter. . . The model for this division is found already here, and the tabernacle becomes an important way of carrying the Sinai experience forward during the subsequent wanderings. . .” (Bound for Freedom, 134).