When Jesus walked on the water, did the disciples worship him or were their hearts hardened?

The two accounts describe the same moment from two sides. Matthew tells what the disciples did: overwhelmed, they worshipped Jesus and said, “Of a truth thou art the Son of God” (Matthew 14:33). Mark tells how they felt, “sore amazed in themselves beyond measure”, and then gives his own comment on why they were so astonished: “they considered not the miracle of the loaves: for their heart was hardened” (Mark 6:51–52). ‘Hardened’ (Greek pepōrōmenē, from pōroō) here means dull and slow to understand, not hostile. Jesus uses the same word when he asks the disciples, “have ye your heart yet hardened?”, because they still had not grasped what the feeding miracles meant (Mark 8:17).

Amazement, worship and slow understanding can all be true of the same people at the same time. Had they grasped what the feeding of the five thousand showed about Jesus, they would not have been so astonished to see him master of the wind and the sea. Their cry in the boat was real worship, but their understanding had not caught up with it. Matthew does not hide this. In the same scene Peter’s faith fails on the water, and Jesus says, “O thou of little faith, wherefore didst thou doubt?” (Matthew 14:31). Later he asks them all, “Do ye not yet understand, neither remember the five loaves?” (Matthew 16:9).