While Jesus and his disciples were in a boat crossing a lake (possibly the Sea of Galilee), a storm frightened his disciples while Jesus slept. They awoke Jesus, fearful that the storm would harm them. Jesus then miraculously calmed the storm.
As explained in the Gospel of Matthew:
He replied, "You of little faith, why are you so afraid?" Then he got up and rebuked the winds and the waves, and it was completely calm.
The men were amazed and asked, "What kind of man is this? Even the winds and the waves obey him!"
- Matthew 8:23-27, NIV translation.
Read more in the book Jesus the Miracle Worker: The 46 miracles of Jesus explained in chronological order (The Jesus Books) -- now available at amazon.