Deuteronomy 19:5
As when a man goeth into the wood with his neighbour to hew wood, and his hand fetcheth a stroke with the axe to cut down the tree, and the head slippeth from the helve, and lighteth upon his neighbour, that he die; he shall flee unto one of those cities, and live:
The verse stands in the fifth and last book of the Pentateuch and falls in Deuteronomy 18 to 21, within chapters 5 to 26, which form Moses's second address given just before his death reviewing the law for the new generation, the section from which the book is named Deuteronomy meaning second law or duplicate of the law. The stroke is made with the axe, because the Hebrew letter beth when joined as a preposition to a tool, weapon, or instrument means with, not under. Beth means in, within, or with, and under in the sense of beneath comes from other words or from part of a verb, except in the sense of within, as within the shelter of the wing or within the earth. The same rule governs with an ax, with axes, and with nails and with hammers, and proves that put under saws and axes means put to work with them.
The verse belongs to a law that restricts and restrains blood revenge. The Hebrew custom authorizing and even requiring the next of kin to avenge a murdered person by killing his murderer was too deeply rooted to be suddenly abolished, so the Mosaic law provided cities of refuge where a homicide could flee for safety, escape private vengeance, and claim a fair trial. That provision protects one who kills accidentally by distinguishing an unintended death from murder, while not providing a guilty murderer a way to evade the legal consequences of his crime. The verse gives the example of an accidental and unwitting killing while two neighbors are cutting wood together, when the axe head slips from its handle and strikes the other man dead. The survivor who caused the death without intent must and may flee to a designated city of refuge and live there to save his life, rather than be treated as an intentional or willful murderer before a legal investigation or be handed over to the avenger of blood.
God's provision of a city of refuge where one in danger can flee and live remains the pattern. It calls for a literal place of refuge for Jews who after accepting Christ are bitterly persecuted and must leave their countrymen. That place is to give them work and at the same time train them to be workers for others.