After my husband underwent heart surgery, I spent an anxious night by his hospital bed. Mid-morning, I remembered a scheduled haircut. “I’ll have to cancel,” I said, raking my fingers distractedly through my straggly hair.

“Mom, just wash your face and go to your appointment,” my daughter said.

“No, no,” I insisted. “It doesn’t matter. I need to be here.”

“I’ll stay,” Rosie said. “Self-care, Mom. . . . Self-care. You’re of more use to Dad if you take care of yourself.”

Moses was wearing himself out serving alone as judge over the Israelites. Jethro cautioned his son-in-law Moses: “You will only wear [yourself] out.…