Matthew Poole and continuators on Judges 19:29

29 ¶ And when he was come into his house, he took a knife, and laid hold on his concubine, and divided her, together with her bones , into twelve pieces , and sent her into all the coasts of Israel .

Or, according to her bones, according to the joints of her Body, for there he made the division. This might seem to be a Barbarous and inhuman act in it self; but may seem excusable if it be considered, that the sadness of the Spectacle did highly contribute to stir up the zeal of all the Israelites to avenge his Concubines death, and to execute Justice upon such profligate Offenders; and was necessary, especially in this time of Anarchy and general Corruption, Iudg. 17. 6. to awaken them out of that Lethargy, in which all the Tribes lay.

That one piece might be sent to every Tribe; whereof none to Levi, because they would meet with it in every Tribe, being dispersed among them; but one to Benjamin; for he might well presume, that they would as much abhor so villanous an Action, though done by some of their own Tribe, as any of the rest.

By several messengers, by whom also he sent a particular Relation of the Fact.