As can be seen from Jn 6:17, Jesus Christ, having commanded the disciples to set out alone for the western side of the sea, promised to come to them in the boat at some point on the shore. From this one may conclude that the disciples first had to keep a coastal course toward the northern end of the sea.
But suddenly a north-eastern wind arose and began to drive the boat south-westward, into the depth of the sea. In such a situation they probably wished to reach quickly the place to which they were sailing by the Lord's command. Yet they struggled until the fourth watch and did not reach the shore.
At that time, when they were in the midst of the sea, according to Matthew and Mark, and had sailed about twenty-five or thirty stadia, according to John, they saw Jesus walking on the waters and directing His way past them, Mk 6:48. Exhausted by their struggle with the waves and by fear for their lives, they did not believe their eyes. They took Him for a phantom, and fear seized them still more. But Jesus Christ encouraged them with His voice.
Here follows the account found only in the Evangelist Matthew, concerning the Apostle Peter's walking on the waters, Mt 14:28-31.
The Evangelists end the story differently. First of all, the Evangelist John seems to contradict Matthew and Mark. According to the latter, the disciples received Jesus, and Peter according to Matthew, into the boat, and the wind ceased. But John says, "They wanted to receive Him into the boat, and immediately the boat reached the shore to which they were going."
It might seem that the meaning is this: the disciples only wished to receive Jesus into the boat, but this proved unnecessary, because the boat reached the shore. Yet it is not necessary to represent the matter in this way.
"They wanted" is set against their previous state, their fear that they saw not Jesus but a phantom. This fear had now passed, and they wanted to receive Him into the boat, whereas before they wanted to flee from Him.
"Immediately" is set against their previous, very prolonged, yet unsuccessful struggle with the waves. It is not necessary to understand this word to mean that Christ did not have to sail some distance with the disciples. Five to ten stadia still remained to the shore.
"Immediately" means only that the sailors, now with Jesus, reached the shore as quickly as before they had long and unsuccessfully labored to attain it. What the first Evangelists indicated with the words, "and the wind ceased," John expresses by continuing the same thought: "immediately the boat reached the shore."
Then Matthew and Mark seem to contradict one another. The former says that the disciples worshiped the Lord and confessed Him as the Son of God after they were assured by the miracle of Jesus Christ's walking on the waters. The latter says that the disciples' heart was hardened, that they had not understood the miracle of the loaves, and that now they only marveled and were amazed at the new miracle, Mk 6:51-52.
From this, however, it follows only that the disciples, struck by the greatness of the miracle, bowed before the Lord and confessed Him as the Messiah. Yet at the same time they wondered that Christ performed such extraordinary and unheard-of works.
The Apostle Peter, from whose words Mark speaks here, observed in the depths of the disciples' soul such a disposition and reflection. He regarded it as a defect, a hardening of heart. In his view, the miracle of the feeding was so great that after it there should have been no place for any questions about the power or possibility for Jesus Christ to perform even such a miracle as walking on the waters.
Since in the first three Evangelists it is said that evening had already come before the feeding, Mt 14:15, here a second evening must be understood. Among the Jews the first evening was from three to six o'clock, and the second from sunset until the onset of night darkness.
In the time of Christ, the Jews divided the night into four watches of three hours each. The fourth watch was from three to six o'clock in the morning.
The whole sea, from east to west, measured forty stadia. According to John, therefore, the disciples were in the middle of the sea. But Matthew and Mark, by the expression "in the midst of the sea," mean only that the disciples were far from shore and therefore, in the stormy sea, were in danger.