Feast of the The Circumcision of Christ & the Eighth Day of Christmas

From the 13th century until the reform of the Calendar by Pope John XXIII in 1960, today was the Feast of the Circumcision of Christ. With John's reforms, it became simply the Octave Day of Christmas.

In the post-Conciliar Calendar of Paul VI it was renamed the Solemnity of Mary, Mother of God. Through all the changes tho', the Gospel has remained that of the Circumcision,

Luke 2:21At that time, when eight days were fulfilled for the circumcision of the Child, His name was called Jesus, the name given Him by the angel before He was conceived in the womb. 

However, in the Mass of Paul VI it has been augmented with verses 16-20,  

  16 And they came with haste; and they found Mary and Joseph, and the infant lying in the manger.17 And seeing, they understood of the word that had been spoken to them concerning this child.18 And all that heard, wondered; and at those things that were told them by the shepherds.19 But Mary kept all these words, pondering them in her heart.20 And the shepherds returned, glorifying and praising God, for all the things they had heard and seen, as it was told unto them.

Circumcision of Christ,
Menologion of Basil II, 979-984

From the Golden Legend of Blessed Jacobus Voragine,

The day of the circumcision of our Lord there be four things that make and show it to be holy and solemn. The first is the octave  of the Nativity. The second the imposition of a new name bearing health. The third the effusion of his precious blood. The fourth the signs of the circumcision. As for the first it appeareth, for the utas of saints be solemn, by much more reason ought it to be of him that is the saint of all saints. Now it seemeth that the Nativity of our Lord ought not to have none utas. For the nativity tendeth to the death. And the decease of saints have their utas because they be born of the nativity that stretcheth to life perdurable, for to be after glorified in body. And by the same way it seemeth that the nativity of the glorious Virgin Mary and of S. John Baptist, and of the Resurrection of our Lord ought not to have utas, for the resurrection was then done. Hereto we ought to consider, like as saith a doctor, that, in this we should fulfil such things as we accomplished not in the principal day that our Lord was born in. Of which of ancient time men were wont to sing at the Mass: Vultum tuum domine, etc. to the honour of our Lady S. Mary. The other octaves or utases as of Paske, Whitsuntide, the nativity of our Lady and S. John Baptist be of devotion, as of other saints that men will honour for singular cause or affection. And they may be said the octaves of figuration, for they signify and figure the octave of the last resurrection perpetual, which is the eighth age. And as to the second, this day was his name imposed to him, and was named with the new name that the mouth of God named. This is the name of which there is none other under heaven by which we may be saved, that is Jesus. After S. Bernard: This is the name which in the mouth is honey, in the ear melody, and in the heart joy; this is the name after that he saith, it lighteth and shineth like oil. When it is preached it feedeth the soul, when it is in the mind of the heart it is sweet, and it anointeth when it is called. And as the evangelist saith, he had three names, that is to wit the Son of God, Jesus, and Christus. He is called the Son of God insomuch as he is God of God the Father; Christ insomuch as he is a man taken of a person divine and nature human, and Jesus inasmuch as he is God united to our humanity. And of this three manner of names, saith S. Bernard: Ye that lie in dust and powder arise out of your sleep and awake ye and give praising to God. Lo here that our Lord shall come unto your health, he cometh with unction, he cometh with glory. Jesus cometh not without health, nor Christ cometh not without unction, nor the Son of God without glory. For he is our health, our unction and our joy. And as touching this treble name; before his passion, he was not perfectly known. As touching the first he was somewhat known by conjecting, as of his enemies, which said Jesu Christ to be the Son of God. And as to the second, of less or fewer he was known for Jesu Christ. And as to the third, vocally, for as much as by the voice he was called Jesus. But as to the reason of the name, he was not known. For Jesus is as much to say as Saviour, and this understood not they. After the resurrection, this treble was clarified and declared. The first to the certainty, the second to the publication, the third to the reason of the name. The first name is Son of God. And that these names be appropriate to him, Saint Hilary in his book that he made of the Trinity saith thus: Vere filium Dei unigenitum. In divers manners this name, Son of God, is known, as it is witnessed of God. God the Father witnesseth it that he is his son. Apostles preach it, the religious believe it, the fiends our enemies confess it. And therefore we know our Lord Jesu Christ in his manners, by name, by nature, by nativity, by puissance, and by his passion. The second name is Christus, which is interpreted unction. For he was anointed with the oil of gladness before all them that to him were party. And by that he is said anointed, it is showed that he was a prophet, a champion, a priest and a king. These four persons sometime were wont to be anointed. Jesu Christ was a prophet teaching the doctrine divine, a champion in the battle against the devil whom he overcame, a priest in reconciling the human lineage to God the Father, and a king in distributing and rewarding every man. Of this second name we be all named, for of this name Christ we be called christian men. Of which name S. Austin saith thus: Every christian man ought to be c puissance or might is to him perdurable, the second, of might of habitation, is to him sith the beginning of his conception, like as the angel showed, and after that he hath puissance of deed and work. was imposed to him of Joseph, because of his passion that was to against original sin, the devil weened that he that received it were a sinner, and had need of the remedy of circumcision. And for this cause Jesu Christ would that his mother being alway a virgin should be married, because that by the sacrament of matrimony his Incarnati purpose is for to leave sin and take the good, the which is showed us by the son that dispended his good follily, and when he had perceived that he had done evil and foolishly, he advertised himself and said: I shall depart and return to my father, and shall pray that I may serve him, and that he may receive me to mercy, and make me as one of his servants. The third is shame of sin, whereof saith S. Paul to them that for their sins be in pain and in torment: What fruit have ye founder in those sins in your life of which now ye be ashamed? The fourth is dread of the coming judgment and doom, whereof Job saith: I have feared and doubted God as men dread the waves of the sea in their great rage and tempest. And S. Jerome saith thus: Sive comedam sive bibam, etc. As oft as I eat or drink or that I do any other thing, alway me seemeth that I hear the sound and the voice crying: Arise, ye dead men, and come to the doom and the judgment. The fifth is contrition, whereof S. Jerome saith: Give thy weeping and bitterness of that which thou hast angered thy God by thy sin. The sixth is confession, whereof David saith: Dixi confitebor, etc.: I have said and purposed in my heart that I shall confess me to God and make knowledge of my sin. The seventh is hope of pardon, for if Judas had had very repentance and hope, and had confessed his sin, he had had forgiveness and pardon. The eighth is satisfaction and sacrifice, and then is the man verily circumcised, not only from the sin, but also from pain. Where the two first days be for the sorrow of sin that hath been done and the will for to amend it, the third day we should confess the evil that we have done and the good deeds that we have left. The other four days be orison, effusion of tears, affliction of body, and alms given. Or otherwise by these eight days may be understood eight things, of which the considerati the nativity of Jesu Christ that is called the day of circumcision, we find that Jesu Christ said by the mouth of his saints: Non veni legem solvere sed adimplere; I came not, said Jesu Christ, to break the law, but to fulfil it. And he was that day circumcised and named Jesus, which is as much to say as Saviour. And at the circumcision must he cut a little of the skin at the end of the member or yard, and that is signified and shewed that we ought to be circumcised, and cut and taken away from us the sins and evil vices, that is to wit pride, wrath, envy, covetousness, sloth, gluttony, and lechery, and all sins, and purge us by confession, by contrition, by satisfaction, by almsdeeds, and by prayers, and to give for God's sake of the goods that he hath lent us. For we have nothing proper, but Jesu Christ hath lent to us all that we have. Then it is well reason that we do give for him to the poor of such goods as be his, for we be but servants, and we ought to give to the hungry meat, to the thirsty drink, to the naked clothing, visit the sick, and tofore all things to love God, and after, our neighbour as ourself; and despoil ourself from sin, and clothe us with good works and virtues, and follow the commandment of Jesu Christ. And in this manner we shall fulfil the will of our father Jesu Christ, if we been so purged and thus circumcised. Then let us pray unto the Lord of heaven that saith that he came not to break the law but to fulfil it, that he give us grace in such manner to fulfil the law and his will in this world, that we may come into his holy bliss in heaven. Amen.

The Circumcision, by Luca Signorelli

The Homily from Matins of the Feast

Homily by St. Ambrose, Bishop of Milan.
Book ii on Luke ii
So the Child is circumcised. This is the Child of Whom it is said: Unto us a Child is born, unto us a Son is given, Isa. ix. 6. Made under the law to redeem them that were under the law. Gal. iv. 4. To present Him to the Lord, 22. In my Commentary on Isaiah I have already explained what is meant by being presented to the Lord in Jerusalem, and therefore I will not enter into the subject again. He that is circumcised in heart gaineth the protection of God, for the eyes of the Lord are upon the righteous. Ps. xxxiii. 16. Ye will see that as all the ceremonies of the old law were types of realities in the new, so the circumcision of the body signified the cleansing of the heart from the guilt of sin. 

But since the body and mind of man remain yet infected with a proneness' to sin, the circumcision of the eighth day is also a type of that complete cleansing from sin which we shall have at the resurrection. This ceremony was also performed in obedience to the commandment of God: Every male that openeth the womb shall be called holy unto the Lord. These words were written with especial reference to the delivery of the Blessed Virgin. Truly He That opened her womb was holy, for He was altogether without spot, and we may gather that the law was written specially for Him from the words of the Angel: That Holy Thing Which shall be born of thee, shall be called the Son of God.

Among all that are born of women the Lord Jesus Christ stood alone in holiness. Fresh from His immaculate Birth, He felt no contagion from human corruption, and His heavenly Majesty drove it away. If we are to follow the letter and say that every male that openeth the womb is holy, how shall we explain that so many have been unrighteous? Was Ahab holy? Were the false prophets holy? Were they holy on whom Elijah justly called down fire from heaven? But He to Whom the sacred commandment of the law of God is mystically directed is the Holy One of Israel; Who also alone hath opened the secret womb of His holy Virgin-bride the Church, filling her with a sinless fruitfulness to give birth to Christian souls.

And it's the Eighth Day of Christmas.

On the eighth day of Christmas my true love sent to me
8 maids a-milking.