The disciples' faith is tested before Jesus calms the stormy sea.
Mark 4 :37-40
37 And there arose a great storm of wind, and the waves beat into the ship, so that it was now full.
38 And he was in the hinder part of the ship, asleep on a pillow: and they awake him, and say unto him, Master, carest thou not that we perish?
39 And he arose, and rebuked the wind, and said unto the sea, Peace, be still. And the wind ceased, and there was a great calm.
40 And he said unto them, Why are ye so fearful? how is it that ye have no faith?