Exodus 37:4

And Bezaleel made the ark of shittim wood: two cubits and a half was the length of it, and a cubit and a half the breadth of it, and a cubit and a half the height of it:

And he overlaid it with pure gold within and without, and made a crown of gold to it round about.

And he cast for it four rings of gold, to be set by the four corners of it; even two rings upon the one side of it, and two rings upon the other side of it.

And he put the staves into the rings by the sides of the ark, to bear the ark.