Acts 1:15

“Accordingly, after one of these had been struck off, He commanded the eleven others, on His departure to the Father, to "go and teach all nations, who were to be baptized into the Father, and into the Son, and into the Holy Ghost." [Matt. 28:19] Immediately, therefore, so did the apostles, whom this designation indicates as "the sent." Having, on the authority of a prophecy, which occurs in a psalm of David, [Ps. 109:8] chosen Matthias by lot as the twelfth [Acts 1:15-20], into the place of Judas, they obtained the promised power of the Holy Ghost for the gift of miracles and of utterance; and after first bearing witness to the faith in Jesus Christ throughout Judæa, and founding churches (there), they next went forth into the world and preached the same doctrine of the same faith to the nations. They then in like manner founded churches in every city, from which all the other churches, one after another, derived the tradition of the faith, and the seeds of doctrine, and are every day deriving them, that they may become churches. Indeed, it is on this account only that they will be able to deem themselves apostolic, as being the offspring of apostolic churches.”

“"And in those days," it says, "Peter stood up in the midst of the disciples, and said." Both as being ardent, and as having been put in trust by Christ with the flock, and as having precedence in honor, he always begins the discourse. ("The number of the names together were about an hundred and twenty.) "Men and brethren," says Peter. For if the Lord called them brethren, much more may he. "Men," he says: they all being present. See the dignity of the Church, the angelic condition! No distinction there, "neither male nor female." I would that the Churches were such now! None there had his mind full of some worldly matter, none was anxiously thinking about household concerns. Such a benefit are temptations, such the advantage of afflictions! Again, consider the moderation of James. He it was who received the Bishopric of Jerusalem, and here he says nothing. Mark also the great moderation of the other Apostles, how they concede the throne to him, and no longer dispute with each other. For that Church was as it were in heaven: having nothing to do with this world's affairs: and resplendent not with walls, no, nor with numbers, but with the zeal of them that formed the assembly. They were "about an hundred and twenty," it says. The seventy perhaps whom Christ Himself had chosen, and other of the more earnest-minded disciples, as Joseph and Matthias. There were women, he says, many, who followed Him. "Together" they were on all occasions.”

“Foremost among the band of apostles, Peter had been called from his small boat; the scaly throng were wont to be caught by this fisher; suddenly, seen from the shore as he drew [his nets], he himself deserved to be drawn; Christ's fishing deigned to seize a disciple who must stretch the nets which are to catch the human race. To the hand that had borne the fishhook was transferred the key. He who had been eager to shift the dripping booty from the depths of the sea to the shore and to fill the craft with spoils, now in another area draws from the better waves [of baptism]; no longer pursuing his profits through the waters, he forsakes his profession. To him the Lamb entrusted the sheep which he saved by his passion; and he enlarges his flock throughout the whole world under this shepherd.”

“"And in those days Peter rising up in the midst of the brethren, said, "etc. At that moment blessed Peter, quoting Psalm 108, said in the midst of the brethren, who were about a hundred and twenty in number: "Now that Judas the traitor is gone, we must think of the twelfth apostle," for the perfect number to be completed. Then, having placed Joseph and Matthias in the middle and said a prayer, they cast lots, and the election fell upon Matthias, and he was numbered as the twelfth apostle.”

“There was, however, a crowd of about a hundred and twenty people together. These hundred and twenty, gradually rising from one to fifteen by increments, form the number of the fifteen steps, which mystically signifies the perfection of both laws in the Psalter, and in which the chosen vessel remains with Peter in Jerusalem. For it was necessary that the mystery, which the legislator exhibited in years, should be designated by the preachers of the new grace in their number.”

“Then Peter arose, not James, and as if more zealous, and as one to whom the leadership of the disciples had been entrusted. Moreover James was modest, more suited to speech and quiet, while the others handled affairs. Therefore they yield the seat [καθέδρας] of Jerusalem to him. But see how he acts by common decree in all things, and not from primacy nor by his own authority. One hundred and twenty were together present of those who had believed in the Lord. For indeed there were seventy, and five hundred whom Paul says he saw the Lord after he had risen (1 Cor. 15:6). But it is likely that these were among those who had been more approved and were more fervent in speaking freely.”