The men had never seen anything like this, and their question is pure astonishment. A moment earlier they had cried, "we perish" (Matthew 8:25). Now Jesus had rebuked the winds and the sea, and there was a great calm. Matthew Henry writes, "They never saw a storm so turned at once into a perfect calm." Barnes explains "what manner of man" as "what kind of a personage," and says they felt that none but God could calm such a storm. Gill describes them as "filled with astonishment and fear, or reverence." They were not asking for information. They were struggling to take in who was with them in the boat.

No one answers the question in the boat, and Matthew leaves it hanging. But the very next scene gives a startling answer: across the sea, devils cry out to Him, "Jesus, thou Son of God" (Matthew 8:29). Later, after Jesus walks on the water and the wind ceases, "they that were in the ship came and worshipped him, saying, Of a truth thou art the Son of God" (Matthew 14:32-33).

"What manner of man" translates potapos. Thayer notes that the word first meant "from what country, race, or tribe?" and came to mean "of what sort or quality? (what manner of?)." The men were asking what kind of being Jesus could be.

Matthew calls the speakers simply "the men." Gill notes that Matthew seems to ascribe it to "the mariners that were in the ship," while the other Gospels seem to refer it to the disciples, and he thinks it likely the miracle affected both. Mark says, "they feared exceedingly, and said one to another" (Mark 4:41), and Luke, "they being afraid wondered, saying one to another" (Luke 8:25). The KJV ends this sentence with an exclamation mark, as a cry of wonder.

This question is the right question about Jesus. His own followers, who had followed Him into the ship (Matthew 8:23), now see the wind and the sea obey Him, and they ask out loud who He is. Matthew Henry draws the lesson: "He that can do this, can do any thing."

The disciples' wonder is followed at once by the demons' cry, "thou Son of God" (Matthew 8:29). The disciples were still asking; the demons already knew. Matthew lets the reader see that the answer to the disciples' question is greater than they yet understood.