Adam Clarke on 2 Kings 13:21

They spied a band - They saw one of these marauding parties; and through fear could not wait to bury their dead, but threw the body into the grave of Elisha, which chanced then to be open; and as soon as it touched the bones of the prophet, the man was restored to life. This shows that the prophet did not perform his miracles by any powers of his own, but by the power of God; and he chose to honor his servant, by making even his bones the instrument of another miracle after his death. This is the first, and I believe the last, account of a true miracle performed by the bones of a dead man; and yet on it and such like the whole system of miraculous working relics has been founded by the popish Church.