The Great Commentary of Cornelius a Lapide: S. Luke
Another and a certain privilege was common to Peter with all his successors, that he and all the other bishops of Rome (for Peter, as Christ willed, founded and confirmed the Pontifical Church at Rome), should never openly fall from this faith, so as to teach the Church heresy, or any error, contrary to the faith. So S. Leo (serm. xxii.), on Natalis of SS. Peter and Paul; S. Cyprian (Lib. i. ep. 3), to Cornelius; Lucius I., Felix I., Agatho, Nicolas I., Leo IX., Innocent III., Bernard and others, whom Bellarmine cites and follows (Lib. i. de Pontif. Roman).
For it was necessary that Christ, by His most wise providence, should provide for His Church, which is ever being sifted and tempted by the devil, and that not only in the time of Peter, but at all times henceforth, even to the end of the world, an oracle of the true faith which she might consult in every doubt, and by which she might be taught and confirmed in the faith, otherwise the Church might err in faith, quod absit! For she is, as S. Paul said to Timothy, “the pillar and ground of the truth” (1 Tim. iii. 15). This oracle of the Church then is Peter, and all successive bishops of Rome. This promise made to Peter and his successors, most especially applies to the time when Peter, as the successor of Christ, began to be the head of the Church, that is, after the death of Christ.
And when thou art converted , strengthen thy brethren, “ From the sifting of Satan, that is from his temptation and from the sin by which thou wilt deny Me ; for by this thou wilt be turned aside from Me, and My grace and love.” So Euthymius, Theophylact, Jansen, F. Lucas, and others.
Some take this converted (conversus) as meaning “again” (iterum). So Bede, “ Do thou, O Peter, again confirm the Apostles , in the faith after My death, whom I now, while alive, strengthen by My words.” For the Hebrew often uses the verb for the adverb. So Ps. lxxxv. 6.
Strengthen thy brethren. Thy brethren, and therefore Mine. The condescension of Christ here is wonderful. He does not call the Apostles sons although He spiritually begot them to God, but as well because Christ as man, was the brother of all men, being a sharer of the same human nature, as because the Apostles in their apostleship and preaching of the Gospel, were the brothers and colleagues of Christ ; for they did the same work as He. Hence the Fathers, whom I have cited, and the Doctors of the Church conclude that Peter was set over the other Apostles by Christ, and consequently was made the head and chief over the whole Church, that he might build up, perfect, and confirm the Church in the faith and religion of Christ.
Ver. 36. — But now he that hath a purse , let him take it, and likewise his scrip. A purse filled with money, a scrip with food, that they might have support in the impending persecution ; for they will never find either, “because men will fly from Me, who am bound and accused, and consequently from My disciples as men wicked and condemned.”
And he that hath no sword, let him sell his garment , and buy one . Christ, in these words, did not command them to take a purse and a scrip, and to sell their garment and buy a sword, for He soon after forbade Peter to draw his sword ; but they were a warning of the fierce persecution which was about to fall upon Himself and the apostles, and which was so heavy to those that regarded the difficulty of the case with the eyes of mere human wisdom, that food and weapons would appear things absolutely necessary for the preservation of life. The meaning therefore is this, “ Everything, so far, has happened to you, O my Apostles, well and prosperously ; for when I sent you to preach the Gospel without purse, or scrip, or sword, you were kindly received by most, fed, and sheltered, and had no need of these things. But now so grievous a persecution is impending over you, and so great is the danger to your lives, that in human prudence it may seem necessary to each to think of the preservation of his life, and therefore to take a scrip and purse for provision, and a weapon for defence, and to sell his cloak, and buy a sword. But to Me, who weigh circumstances by the design and decree of God the Father, there is no need of such things ; for I go voluntarily to the cross, and to death, and I offer Myself of My own free will, to those who will persecute Me and crucify Me, so that I may conform Myself to the will of My Father.” So S. Chrysostom (Hom. 85 on S. Matt.), and from him Theophylact on this passage, Jansen, Maldonatus, and others. S. Ambrose says well, “ O Lord, why commandest Thou me to buy a sword, and forbiddest me to strike, unless that I may be prepared for my defence, and that Thou mayest appear able to avenge though Thou wouldst not?”
Ver. 38. — And they said, Lord, behold, here are two swords . They did not understand the mind and words of Christ clearly. He did not mean that they should buy swords, but He wished to show them the impending danger. Christ did not explain His meaning to the Apostles, but concealed it, saying, “It is enough,” meaning that Peter and the other Apostles might carry these swords, and even cut off Malchus’ ear, which He Himself afterwards restored and healed, showing that He was not compelled by force, but was urged by love, willingly and freely to suffer and die. Some think that they were not military swords, but rather large butchers’ knives, which the apostles used for the slaughtering, sacrificing, and disjointing of the Paschal Lamb. So S. Chrysostom, from whom I have said more on Matt. xxvii.
Ver. 39. — And He came out, and went , as He was wont, to the mount of Olives . Bede gives the reason of this : “ The Lord, when about to be delivered up, came to the retirement of this accustomed place, that He might be found the more easily. Where are they who maintained that He feared death, and was crucified against His will ? Christ was wont, in these last days of His life, to preach in the temple by day, and to retire at night to the mount of Olives to pray. This, Judas, as being an Apostle, and a companion of Christ, knew ; and hence he came to this mountain with his followers, and there betrayed and delivered up Christ to them.”
Ver. 43. — And there appeared an angel unto Him from heaven. The angel appeared in a body assumed visibly that he might comfort the eyes and ears of Christ by his appearance and voice.
Jansenius thinks that the angel appeared at each of Christ’s three prayers, and therefore comforted Him three times, to teach us that God always hears those who pray, and gives them grace and strength unceasingly. F. Lucas, and others, think with more reason, that the angel only appeared once, at the third and last prayer, and comforted Him when He prayed more earnestly, and sweated blood, to show that we ought to persevere in prayer, and that the fruit of such perseverance is the comfort of God, and the vision of angels. For after this consolation from the Father by the angel, the agony of Christ seems to have passed away, and He appears to have prayed no more but to have prepared bravely for death. This angel was Gabriel, says Gabriel Vasquez (1. p. tom. ii. disput. 244, No. 3), for Gabriel has his name from his fortitude, Gabriel being Geber-el the man of God, or Gebura-el the fortitude of God ; for he has the office of comforting the weak, afflicted, and fearful. But he comforted Christ not by strengthening His weakness, but by praising His surpassing fortitude. Lud. de Pont thinks the same in his “ Meditation on the Agony of Christ in the Garden,” because Gabriel was the legate and messenger of the economy of Christ, as at the Incarnation (Luke i. 26), and of the seventy weeks of Daniel, which foretold the time of the nativity of Christ.