The Great Commentary of Cornelius à Lapide
Luke 15:5
And when he hath found it, he layeth it on his shoulders, rejoicing. Or as the Arabic renders it, "He carries it on his shoulders joyfully," that he may the more quickly return it to the flock.
In like manner on Christ "was laid," as saith the prophet Isaiah, the iniquity of us all." Hence Gregory of Nyssa, writes in the Catena, "When the shepherd had found the sheep, he did not punish it, he did not drive it to the fold, but placing it on his shoulder, and carrying it gently, he reunited it with the flock." Oh how wondrous is the meekness, clemency, and love of Christ our Lord! It was to represent this love to the faithful that Christ is depicted in our temples with the lost sheep on His shoulders, carrying it back to the flock, and it is related of the son of Charlemagne, that laying aside his royal state, he became a monk, and when employed in keeping sheep, followed to the letter the example set by the Good Shepherd: for humility and the imitation of Christ is in truth the glory of Christian kings.
Ver. 6. Rejoice with me; for I have found my sheep which was lost. Συγχάζητέ μοι, Let My joy be one with yours partake of My joy. His joy is so great that he cannot confine it to Himself, His friends must rejoice also. He further indicates that the event is such a happy one, that it ought to afford matter for rejoicing to all. He says not, "Rejoice with the sheep that is found," but, "with Me." Because truly our life is His joy. S. Gregory. Ver. 7. I say unto you, that likewise joy shall be in heaven, &c., i.e. greater joy, for such is implied by the comparative particle ρ̀, "than."
The angels then, and the saints in heaven rejoice with exceeding great joy when it is made known to them, by the revelation of God, that a sinner is converted; for when such an one by repentance passes from condemnation to life, it is a gain to the sinner to the angels and above all to God Himself.
The sinner passes from sin unto righteousness, from hell to heaven. The angels therefore rejoice at the blessedness of such an one, because, says Euthymius, they are kindly disposed towards men and because by repentance men become like them in purity and in holiness. They rejoice also on their own account because the ruin which was effected by Lucifer and his angels is remedied by the justification and sanctification of men, and because the places from which these angels fell are restored and filled up. It is a joy to God because He is φιλόψυχος, a lover of souls, and thirsts for the salvation of men.
Again the angels rejoice that the desire of God, whom they love above all things, is fulfilled, and that He is a partaker of this joy, as well as honoured by the penitence of the, sinner. Apposite to this matter is the vision of Carpus, to whom Christ made known that He so longed for the conversion of sinners, as to be ready again to suffer death upon the Cross, if thereby this object could be effected. And Palladius relates that a certain Anchorite, who had fallen into sin, repented in sackcloth and ashes with many tears; whereupon an angel appeared to him and said, "The Lord hath accepted thy penitence, and hath had compassion on thee. Take heed that thou art not again led astray."
By this argument, Christ rebukes the Pharisees for murmuring against Him because He companied with sinners in order to convert them. For the conversion of sinners is a work most pleasing to God and His angels. The Pharisees ought therefore to take part in this work, and to share in the rejoicing. For "all the fruit" of the Incarnation, and of the death of Christ upon the Cross is "to take away sin," Isaiah 27:9, "to bring in everlasting righteousness," and to extend the kingdom of God. S. Matthew 6:10. The knowledge of this ought to excite in every follower of Christ a zealous love for the souls of men.
Hence S. Gregory, when he heard that the English had been converted by the preaching of Augustine, rejoiced in spirit, and wrote; "If there is great joy in heaven over one sinner that repenteth, what joy, think you, has there been over the conversion of so great a people; for by their repentance and faith they have condemned the sins which they aforetime had committed. Whilst heaven is thus rejoicing, let us repeat the angelic strain, and let us all with one accord exclaim, 'Glory to God in the highest, and on earth peace, goodwill towards men.'"
More than over ninety and nine just persons. God and His holy angels, then, rejoice over one penitent more than over one righteous man, nay, more than over ninety and nine just persons; because from the conversion of the sinner there arises a new joy, which seems more perceptible, and is in reality felt more than that continuous and long-standing joy which attaches itself to the ninety and nine; a joy which, although actually the greater, seems to men to lose its freshness by reason of its long duration. For the novelty of a thing which we long for awakens in us a vast and a new joy, which is felt all the more on account of its novelty, as we find when we receive tidings of victories or conversions; and Christ often speaks after the manner of men, especially in His parables. The saying of S. Bernard, that "The tears of penitents are the wine of the angels," applies here: The joy over the conversion of a sinner, writes Emmanuel Sà, is sensibly greater. Although in other respects, a man undoubtedly rejoices more over ninety-nine sheep than over one, and God joys more over ninety and nine just persons than over one sinner that repenteth.
S. Gregory adds that God and His angels rejoice the more, because penitents are wont to be more fervent in their love than those who have not fallen away. And elsewhere he says, "The life of fervent devotion which follows after sins committed is often more pleasing to God than that innocence which grows sluggish in its security." "Just as the leader in battle loves that soldier more who, having turned from flight, bravely pursues the enemy, than he who never turned his back and never did a brave act." "And as again the husbandman loves that land more which, after bearing thorns, yields abundant fruit, than that which never had thorns, and never gave him a plentiful crop." Finally (Hom. 34), he cites the example of Victorinus who, having fallen into carnal sin, entered a monastery, and there subjected himself to the severest penance, and so merited to be transfused with the light of heaven, and to hear the voice of God, "Thy sin is forgiven thee!"
If therefore penance be of such avail in a sinner, how great, infers S. Gregory, must be its power in a just man! For many, he says, are conscious of no evil, yet subject themselves to austerities as extreme as if they were beset by every kind of sin. They eschew all things, even such as are lawful, they gird themselves about with a lofty disdain of earth and earthly things, they consider every pleasure forbidden, they deprive themselves of such good things as are allowed them, things that are seen they despise, they yearn for the things which are invisible, they rejoice in mourning, in all things they humble themselves, and deplore sins of thought, as many mourn over sins actually committed.