17
And thou shalt make a mercy-seat of pure gold: two cubits and a half shall be its length, and a cubit and a half its breadth.
Exodus 25:17
Arcana Coelestia #9617
9617. The length of one curtain shall be thirty cubits. That this signifies the fullness of truth from good, is evident from the signification of “length,” as being good (see n. 9487); from the signification of a “curtain,” as being truth from external celestial good (n. 9615); and from the signification of “thirty,” as being what is full (n. 9082).
