Mark 1:17

For by the net of holy preaching they drew fish, that is, men, from the depths of the sea, that is, of infidelity, to the light of faith. Wonderful indeed is this fishing! for fishes when they are caught, soon after die; when men are caught by the word of preaching, they rather are made alive.

(in Marc. i. 6) Now fishers and unlettered men are sent to preach, that the faith of believers might be thought to lie in the power of God, not in eloquence or in learning. It goes on to say, and immediately they left their nets, and followed him.

Look then upon them, living on their own labours, not on the fruits of iniquity; for such men were worthy to become the first disciples of Christ; whence it is subjoined, And Jesus said unto them, Come ye after me. Now He calls them for the second time; for this is the second calling in respect of that, of which we read in John. But it is shown to what they were called, when it is added, I will make you become fishers of men.

(ubi sup.) It may be asked, how he could call two fishers from each of the boats, (first, Peter and Andrew, then having gone a little further, the two others, sons of Zebedee,) when Luke says that James and John were called to help Peter and Andrew, and that it was to Peter only that Christ said, Fear not, from this time thou shalt catch men; (Luke 5:10) he also says, that at the same time, when they had brought their ships to land, they followed him. We must therefore understand that that transaction which Luke intimates happened first, and afterwards that they, as their custom was, had returned to their fishing. So that what Mark here relates happened afterwards; for in this case they followed the Lord, without drawing their boats ashore, (which they would have done had they meant to return,) and followed Him, as one calling them, and ordering them to follow.

We must know also, that action is first called, then contemplation; for Peter is the type of the active life, for he was more ardent than the others, just as the active life is the more bustling; but John is the type of the contemplative life, for he speaks more fully of divine things.