Brewer's: Ring in the Ear
A sign of slavery of life-long servitude.
“Then Eldad took an awl, and, piercing his [Jetur's] ears against the doorpost, made him his servant for ever. The elders pronounced a blessing, and Eldad put a ring through the ears of Jetur, as a sign that he was become his property.” —Eldad the Pilgrim, chap. i.