"For as on the day when you defeated the Midianites you will set the people of Israel free from being slaves to their oppressors like a person removes a yoke from the shoulders of an animal"
Isaiah speaks of the people of Israel as if they were one man. Alternate translation: "For the yoke of their burden ... their shoulders ... their oppressor"
Another possible meaning is "staff," a long piece of wood that a person uses to beat the oxen so they will work and a symbol of one person's power to rule other people.