Numbers 4:6

Then they shall put on it a covering of goatskin and spread on top of that a cloth all of blue , and shall put in its poles .

Then they are to cover the curtain with a durable leather, spread a cloth of solid blue over that and put the poles in place.

And shall put thereon the covering of badgers' skins, and shall spread over it a cloth wholly of blue, and shall put in the staves thereof.