Mark 4:35–41
35 On that day, when evening had come, he said to them, “Let us go across to the other side.” 36 And leaving the crowd, they took him with them in the boat, just as he was. And other boats were with him. 37 And a great windstorm arose, and the waves were breaking into the boat, so that the boat was already filling. 38 But he was in the stern, asleep on the cushion. And they woke him and said to him, “Teacher, do you not care that we are perishing?” 39 And he awoke and rebuked the wind and said to the sea, “Peace! Be still!” And the wind ceased, and there was a great calm. 40 He said to them, “Why are you so afraid? Have you still no faith?” 41 And they were filled with great fear and said to one another, “Who then is this, that even the wind and the sea obey him?”
If you missed Sunday this week the big idea of this text is that Jesus is Lord over creation. This authority belongs only to God. Note that Jesus doesn't take a quiet moment to pray and ask God the Father to calm the storm. He simply "rebukes" it and demands it be still on the basis of his own authority. So, here it is clear that Jesus is claiming authority that only God has. (See Psalm 107: whole chapter OR v. 1-3 and v. 23-32 ; Psalm 89:9)
This storm must have been terrible because even the disciples, some of whom were experienced fishermen on the Sea of Galilee, thought they were going to die. Yet, Jesus simply commands it to be still and it obeys.
The sea is probably the most unpredictable, uncontrollable part of nature. From my knowledge of sailing (ie. Kevin Costner movies like Waterworld and the Guardian), there is only so much you can do to avoid catastrophe in the midst of a terrible storm. You are completely at the mercy of the sea. In this story the disciples were originally terrified at the sea. Then the object of their fear changed to one more powerful than the sea and they wondered at who he could be that even the wind and the sea obey him.