Thou shalt make an ark of shittim wood. Arks were an ordinary part of the religious furniture of temples in Egypt, and were greatly venerated. They usually contained a figure or emblem, of some deity.
Occasionally they were in the shape of boats; but the most ordinary form was that of a cupboard or chest. They were especially constructed for the purpose of being carried about in a procession, and had commonly rings at the side, through which poles were passed on such occasions.
It must be freely admitted, that the general idea of the "Ark," as well as certain points in its ornamentation, was adopted from the Egyptian religion. Egyptian arks were commonly of sycamore wood. Two cubits and a half, etc.
As there is no reason to believe that the Hebrew cubit differed seriously from the cubits of Greece and Rome, we may safely regard the Ark of the Covenant as a chest or box, three feet nine inches long, two feet three inches wide, and two feet three inches deep.