Matthew Poole and continuators on Exodus 25:11

11 And thou shalt overlay it with pure gold, within and without shalt thou overlay it, and shalt make upon it a crown of gold round about.

Or, A border, raised up above the rest of the Ark as a Crown is above that which it is applyed to, onely a crown is round, and this was square. This was both for ornament, and for the fastning of the covering of the Ark to it.