What is 2. Suffering pain or grief. Pope. Laboring oar, the oar which requires most strength and exertion; often used figuratively; as, to have, or pull, the laboring oar in some difficult undertaking called?

laboring — 2. Suffering pain or grief. Pope. Laboring oar, the oar which requires most strength and exertion; often used figuratively; as, to have, or pull, the laboring oar in some difficult undertaking. (Webster's 1913.)