Luke 5:7

And they beckoned unto their partners becausefrom joy and wondering astonishment they were unable to speak. Ver. 10. Fear not (be not lost in astonishment, from henceforth you are to be fishermen in a higher sense of the word), from henceforth thou shalt catch men. ζωγζω̃ν from ζωγζέω, which means

First, to hunt or catch some living thing, hence the Arabic translates it, from henceforth thou shalt be a fisherman, for thou shalt fish for and take men. Thou, Peter, shalt catch men, not by wounding and disabling them, as wild animals are taken; but as fish which are unhurt by the net, so thou shalt catch men not by violence or force, but through the power and operation of the spirit.

Secondly (if we derive the word from ζω̃ν and ε̉γζομαι or ε̉γείζω, to quicken, or recall to life. Hence S. Ambrose (Hexam., lib. v. cap. vi.) "Thou shalt be a life-giver to men;" and the Syriac, "Thou shalt be a fisher of men, to recall them to life." Fishermen, indeed, catch fish to provide themselves with food, but thou, 0 Peter, art to become a fisher of men, not to destroy them, but to give them life by raising them from the death of sin unto the life of righteousness, for like as fish taken from the water die, so men caught by thee become dead indeed unto sin, but alive unto God, and, in a sense, as fish are assimilated by those who feed on them, so do those who are inclosed in the Gospel net, become in very truth members of Christ. Figuratively, the ship of Peter is the Church, the head of which is Peter and his successors. The Pope is therefore the chief fisherman to whom the words of Christ apply, "Thou shalt catch men." It is the duty, therefore, of the Roman Pontiff directly and by means of others to convert the heathen, as the early occupants of the see of Rome converted the Roman people and sent apostolic men to preach the word of life to heathen lands.

Thus S. Gregory sent Augustine to convert the English people.

S. Ambrose observes, that some men, e.g., the martyrs, like fish, are taken by the hook; others, i.e., the body of the faithful, by the net, and adds, "Nets are the means whereby the Apostles catch men, for nets do not destroy but preserve what they take, and bring to the surface that which is floating below."

Nets are called in Latin "retia," because they are retentive "retinentia," of that which they have taken. Gloss.