Four square it shall be, [being] doubled
That is, when it was doubled; for the length of it, according to
Maimonides F3, was a cubit, which is two spans,
and so, when it was doubled, was but one, and its length and
breadth being alike, as follows:
a span [shall be] the length thereof, and a span [shall be]
the breadth
thereof; a square, which is the measure, the form of the new
Jerusalem, the church of Christ, ( Revelation
21:16 ) and may denote the perfection, firmness, and
immovableness of it, ( Psalms 125:1
) . Some have thought that this breastplate was doubled, in order
to have something enclosed in it: some imagine, that within this
fold were put the Urim and Thummim, which they suppose to be two
words engraved on a stone, and different from the twelve stones
in it; others, that the name of Jehovah was written and put
there, as the Targum of Jonathan and Jarchi on ( Exodus 28:30
) and other Jewish writers, and others, fancy some little images
were put within these folds, the name with the teraphim, and
supposed to be the Urim and Thummim; but if these were hid in the
folds, they could not be seen when consulted; it is most probable
there is nothing put within the double, which was not done for
any such use; but most likely that it might be strong to bear the
weight of the precious stones, put in ouches of gold upon it.
F3 Cele Hamikdash, c. 9. sect. 6.