The sea of Galilee lies in a basin, and is subject to storms caused by a sudden change in atmospheric pressure. On this occasion there was a great storm of wind, of gale force, which quickly had the small boat in danger (4:37). Jesus was asleep in the stern—a detail only in Mark (4:38) who wants wherever he can to stress the humanity of Jesus. He was tired out at the end of the day. But his sleep was a picture of perfect trust in the sustaining and protecting care
Mark 4:35–41