Charles Ellicott Commentary Exodus 25:15

"The staves shall be in the rings of the ark: they shall not be taken from it." — Exodus 25:15 (ASV)

The staves ... Shall not be taken from it. —The staves were to remain always in the rings, whether the ark was in motion or at rest, that there might never at any time be a necessity for touching the ark itself, or even the rings. He who touched the ark imperilled his life. (See 2 Samuel 6:6–7.)