The Great Commentary of Cornelius à Lapide
John 20:22
And when He had said this, He breathed on them, and said unto them, Receive ye the Holy Ghost. Why did He breathe on them? (1.) To signify the nature of the Holy Spirit, as proceeding both from Him and the Father. For as a man by breathing on another imparts to him his breath, so the Father and the Son by breathing produce the Holy Spirit, and communicate to Him their Spirit and Godhead. So S. Augustine (in loc.), Cyril, Bede, and others. This breathing was not the Holy Spirit Himself, but a sign of Him: so that it means, Receive by this breathing,-as by a sign and instrumental cause, the gift of the Holy Spirit.
(2.) To signify that the Holy Spirit was consubstantial with Himself and the Father. (3.) To show that it was He who first breathed into Adam the breath of life. As if He would say, I first gave Adam his natural life by breathing on him, so by breathing on you, do I give you that Holy Spirit which bestows on you supernatural and divine life. I who first created men, am now their re-creator and restorer. See S. Cyril (Lib. xii. 56), Leontius, Euthymius, and S. Athanasius (Quæst. lxiv . ad Antiochum). (4.) S. Cyril and S. Basil (de Spir. Sancto, cap. xvi.) and S. Ambrose (Serm. xx. in Ps. cxviii. [cxix.]) say that Christ, by these words, signified that He breathed into Adam not only breath but grace, and because he had lost grace by sin He restored it in this way to the Apostles, and through them to all men, being in fact the restorer of grace. He seems to say, Receive ye the Spirit which ye lost in Adam's person by sin. Breathe Him forth on penitents in the sacrament of penance, remit through Him their sins and restore them to the life of the Spirit by grace. Hear S. Cyril. "Man was at first made by the Word of God, and God breathed into him the breath of life, and strengthened him by the imparting of His Spirit. But since he fell by disobedience, God the Father refashioned him, and brought him to new life by His Son. And we may learn that as it was He who in the beginning created our nature, and sealed it by His Holy Spirit, so when He began the renewal of our nature, He gives the Spirit to the disciples by breathing on them, that just as we were created by Him at first, we may in like manner also be renewed by Him.
Symbolically. This breathing represents sin as a black cloud. For as a cloud is dispersed by the wind, so is every cloud of sin driven away by the breath of the Spirit. See Is. xliv. And again, it represents the judiciary power of remitting sins, which is exercised by the breath of the voice which says, I absolve thee.
Tropologically. It denotes that a Priest, in order to remit sin, should possess a mighty spirit, charity, and zeal, so as to breathe on penitents and lead them to true penitence, sorrow, and repentance, and thus dispose them for the remission of their sins. And so we see Confessors who are gifted with mighty resolution, wound with the spirit of their mouth many and great sinners, and convert them to holiness. Just as we read that S. Ambrose, when hearing the sins of those who confessed to him, was wont to weep, and thus by his own tears lead them to tears and contrition.
Receive ye the Holy Ghost. The Apostles had already received the Holy Ghost in Baptism and Holy Communion. But they were about to receive His fulness, according to Christ's promise, at Pentecost, in order to the conversion of the Gentiles, when the Holy Spirit descending on them visibly in form of fiery tongues, filled them to the full with all His gifts, and especially with the power of preaching. But here He confers on them the Holy Ghost for another purpose, the remission of sin. "Receive ye the Holy Ghost," that is, power to remit sins by the Holy Ghost. So Theophylact, Euthymius, and Rupertus. This signifies that He came as was prophesied by Isaiah (xxvii. 9), and that both Christ and the Father gave the Holy Ghost. And from hence it is clear that the Holy Ghost is given, not merely by grace making us acceptable (to God), but also by grace given freely, as is the power of remitting sins, which is given to priests even in mortal sin, when they are ordained. For the Holy Ghost is the primary author of grace who works in the sacrament, and by it remits sins, even though its minister be an ungodly man. Whence Cyril and Chrysostom thus expound the passage, Receive the Holy Ghost, that is, the power of remitting sin by the Holy Ghost, co-operating with you in that sacrament and remitting sins. And again, by the Holy Ghost you must understand with S. Augustine (in loc.), and S. Ambrose (Serm. x. in Ps. cxviii. [cxix.]), the very grace and charity of the Holy Ghost. For this was infused into the Apostles more fully and abundantly, and is likewise by the power of the sacrament of order infused into priests at their ordination (unless they put an obstacle and choose to continue in their sins, and refuse to be contrite for their past sins), so that they may duly and without sin administer the sacrament of penitence, and absolve sinners. For a priest who absolves others ought to be free from sin; if not, he is guilty of sin, and yet truly absolves sinners. From these words it is clear that the Holy Ghost has the primary and highest power of forgiving sins, and that He communicated this power to the Apostles, and accordingly that He Himself is truly God. (So S. Basil, Lib. v. contra Eunomium; S. Ambrose, Lib. iii . ch. 19 , de Spir. Sancto, and S. Chrysostom, Hom. vi . on 2 Cor.) The same power is indeed common to the whole Holy Trinity, but specially belongs to the Holy Ghost, as do Goodness and Love, and all the work of sanctification, just as Power specially belongs to the Father, and to the Son Wisdom, and all its works.
2. Observe that the Holy Ghost and His power of remitting sins are here given them, not only for their own sakes, as about to be judges of sinners in the tribunal of penitence, but also for the sake of penitent sinners themselves. And consequently the same power is given even to wicked priests when they are ordained, as the power of judging in a secular court can be given to a wicked judge. But yet if they dispose themselves by penitence to the right reception of the Sacrament of Ordination, they will receive therein the Holy Ghost even to their own sanctification, to make them the more fit to sanctify others (penitents, for instance), as was here done to the Apostles.
3. S. Cyril (and Maldonatus after him) remarks that the Holy Ghost was here conferred on S. Thomas, even though absent, and with it the consequent power of remitting sins, just as the spirit of prophecy was given by Moses to Eldad and Medad who were absent. But the contrary opinion seems more true. For Thomas was then unbelieving and incapable of receiving the Holy Spirit, and accordingly the Holy Ghost was given him on the eighth day when Christ appeared to him, and converted him by showing him His wounds. So Toletus, Ribera, and others.
Lastly, notice this act of Christ as an example for ecclesiastical ceremonies. Christ, by the ceremony of breathing on them, gave the Apostles the Holy Ghost and the power of remitting sins. Therefore ecclesiastical ceremonies are not useless, frivolous, and superstitious, but seemly, efficacious, and sacred.