מדרש על שמות 37:2

R. Hanina of Sepphoris said that Bezalel made three chests for the ark, two of gold and one of wood. He inserted the wooden chest into one golden one, and then the other golden one into the wooden one. After that he covered the edges with gold in order to fulfill what is written: And he overlaid it with gold within and without (Exod. 37:2), and it is written elsewhere; And shalt make upon it a crown of gold roundabout (ibid. 25:11). From here we learn that a scholar’s “inside” should be as his exterior (i.e., he should not be a hypocrite), since it is said: Thou shalt overlay it with pure gold, within and without shalt thou overlay it (ibid.).

What is meant by Thou shalt overlay it with gold, within and without? He said to him: Even though the wooden casket is to be inserted between them, handle it with the utmost care. Why? Because the Torah, the tablets, and even the broken tablets will be placed within it. Hence treat it with honor, since it is said: Thou shalt put them in the ark (Deut. 10:2); that is, both the (second) tablets and the broken tablets shall be placed inside it. And thou shalt put them in the ark. That is to say, even if you should see students of the Torah who are poor and unfortunate, treat them with respect, for the law is stored within them. And make a crown of gold (Exod. 37:2). Why? Because the Torah rests therein. There are three crowns, the crown of the Torah, the crown of priesthood, (and) the crown of kingship, but there is an additional crown, the crown of a good name, that excels them all. How do we know abut the crown of the Torah? It is said: That wisdom preserveth the life of him who has it (Exod. 7:12) both in this world and the world-to-come. Hence it is written: And made a crown of gold.

Why was the acacia-wood placed in between? Because the Torah is called the tree of life, as it is said: She is a tree of life to them that lay hold upon her (Prov. 3:18). He overlaid it with pure gold (Exod. 37:2). Because the words of the Torah are more precious than gold, yea, than fine gold, as is said: More to be desired are they than gold, yea, than much fine gold (Ps. 19:11). And thou shalt make staves of acacia-wood wherewith to bear the ark (Exod. 25:15). They bore the ark with them, and it bore away the sins of Israel, for the Torah within it carries away the sins of Israel.¹²The Hebrew word nasa’ means both “to bear” “to forgive.”