Commento su Esodo 25:11

מבית ומחוץ תצפנו WITHIN AND WITHOUT SHALT THOU OVERLAY IT — Bezalel made three arks, two of gold and one of wood, each having four walls (sides) and a bottom, being, however, open at the top. He put the wooden ark into the larger golden one and the smaller golden one into that of wood and covered its upper rim (that of the wooden ark) with gold; consequently it can be said that the wooden ark was overlaid with gold within and without (Yoma 72b; Jerusalem Talmud Shekalim 6:1).

זהב טהור, this does not mean that gold cannot become ritually impure; we know it can become defiled from Numbers 31,22. The expression טהור here means: ”pure, refined.”

וצפית אותו זהב טהור מבית ומחוץ תצפנו, “you are to overlay it with pure gold, from the inside and the outside you are to overlay it.” This verse is used by our sages (Yuma 72) to demand that Torah scholars must be able to demonstrate that they practice what they preach. They base this on the Ark which was gold on the inside as well as on the outside. Although no one actually saw the inside, it had to correspond to its exterior. Another verse which alludes to this subject is Job 29,14: “I clothed myself in righteousness and it robed me; Justice was my cloak and turban.” The repetition in this verse means that one’s inside must match the image one creates for oneself on the outside. Our sages add further on this subject: “why were the words of Torah compared to glass?, i.e. (Job, 28,17) “gold or glass cannot match its value?” Answer: just as glass is transparent and allows you to see not only the outside but also the interior, so bearers of Torah must be able to be equally transparent, not hiding character weakness not visible to their students or to their peers.