What does Matthew 8:23 mean?

Recently, Jesus responded to the growing crowds around Him (Matthew 8:18). He instructed His disciples to go with Him, by boat, to the other side of the Sea of Galilee, which was the size of a large lake. Now Jesus climbs into the boat and they climb in after Him, beginning to set out on the water. This was probably another instance where Jesus chose to take some time away from the spotlight (Matthew 14:23; Luke 6:12). Since we find Him fast asleep in the following verses, He was likely quite tired.

A 2,000-year-old fishing boat was found in this region in 1986. That boat was about 26 feet long, or about 8 meters, and could hold 15 men. It may have included a single, simple sail. This boat may have been similar to the boat used in this passage.

This body of water is relatively shallow, and the hills around it are steep. This lends itself to extreme changes in wind and weather. Calm seas can become choppy and dangerous quickly, which is what apparently happens during this trip (Matthew 8:24).