Why are ye fearful? - You should have remembered that the Son of God, the Messiah, was on board. You should not have forgotten that he had power to save, and that with him you are safe. So Christians should never fear danger, disease, or death. With Jesus they are safe. No enemy can reach him; and as he is safe, so they shall be also, John 14:19.
Rebuked the winds - Reproved them, or commanded them to be still. What a power was this! What irresistible proof that he was divine! His word awed the tempest and allayed the storm! There is not anywhere a sublimer description of a display of power. Nor could there be clearer proof that he was truly the Son of God.
A great calm - The winds were still, and the sea ceased to dash against the vessel and to endanger their lives.