Charles Ellicott Commentary Judges 19:1

"And it came to pass in those days, when there was no king in Israel, that there was a certain Levite sojourning on the farther side of the hill-country of Ephraim, who took to him a concubine out of Beth-lehem-judah." — Judges 19:1 (ASV)

On the side of Mount Ephraim. —Literally, on the two thighs (yarcethaim) . (Isaiah 37:24.) As to the residence of the Levite at Mount Ephraim, see Note on Judges 17:8. It is probably a fortuitous coincidence that both this Levite and Jonathan have connections with Mount Ephraim and with Bethlehem.

Took to him a concubine. —Such connections were not legally forbidden; yet it is probable that in the case of all but princes or eminent men they were looked on with moral disapprobation. She is called “a wife or concubine”— i.e., a wife with inferior rights for herself and her children.