37 The question may indeed be raised as to how John gives us this account of the calling of the disciples, which is to the effect that, certainly not in Galilee, but in the vicinity of the Jordan, Andrew first of all became a follower of the Lord, together with another disciple whose name is not declared; that, in the second place, Peter got that name from Him; and thirdly, that Philip was called to follow Him; whereas the other three evangelists, in a satisfactory concord with each other, Matthew and Mark in particular being remarkably at one here, tell us that the men were called when they were engaged in fishing.
Luke, it is true, does not mention Andrew by name. Nevertheless, we can gather that he was in that same vessel, from the narrative of Matthew and Mark, who furnish a concise history of the manner in which the affair had gone about. Luke, however, presents us with a fuller and clearer exposition of the circumstances, and gives us also an account of the miracle which was performed there in the haul of fishes, and of the fact that previous to that the Lord spoke to the multitudes when He was seated in the boat.
There may also seem to be a discrepancy in this respect, that Luke records the saying, “From henceforth you shall catch men,” as if it had been addressed by the Lord to Peter alone, while the others have exhibited it as spoken to both the brothers. But it may very well be the case that these words were spoken first to Peter himself, when he was seized with amazement at the immense multitude of fishes which were caught, and this will then be the incident introduced by Luke; and that they were addressed to the two together somewhat later, which [second utterance] will be the one noticed by the other two evangelists.
Therefore the circumstance which we have mentioned with regard to John's narrative deserves to be carefully considered; for it may indeed be supposed to bring before us a contradiction of no slight importance. For if it be the case that in the vicinity of the Jordan, and before Jesus went into Galilee, two men, on hearing the testimony of John the Baptist, followed Jesus; that of these two disciples the one was Andrew, who at once went and brought his own brother Simon to Jesus; and that on this occasion that brother received the name Peter, by which he was thereafter to be called—how can it be said by the other evangelists that He found them engaged in fishing in Galilee, and called them there to be His disciples? How can these diverse accounts be reconciled, unless it be that we are to understand that those men did not gain such a view of Jesus on the occasion connected with the vicinity of the Jordan as would lead them to attach themselves to Him for ever, but that they simply came to know who He was, and, after their first wonder at His Person, returned to their former engagements?
Source: The Harmony of the Gospels (New Advent)