It was a tradition among Arab women that they would not put their child to sleep while they were crying, out of fear that grief would penetrate their body and run through their veins. They would try to make the child smile and strive to make them happy so that they could sleep peacefully, which would strengthen their body, improve their complexion and blood, and give rest to the mind.

— Muruj adh-Dhahab | Al-Masudi