Exodus 25:13-15

And thou shalt make staves of shittim wood, and overlay them with gold.

Thou shalt make staves of shittim wood. These staves, which were to be ornamented in the same style as the ark itself, were always to remain in the rings, even when the ark was stationary, to prevent it from being desecrated by the contact of human hands. The Septuagint has: hoi anaforeis akineetoi, the poles not to be moved (see the note at Numbers 4:15).