Both the Old Testament prophet Micah (5:2) and the Gospels (Mt. 2 & Lk. 2) point to Bethlehem. The knowledge of the place was, as well, passed down among the Christians of Judea. In the third century AD, Origen of Alexandria wrote,

In Bethlehem the cave is pointed out where He was born, and the manger in the cave where He was wrapped in swaddling clothes. And the rumor is in those places, and among foreigners of the Faith, that indeed Jesus was born in this cave who is worshiped and reverenced by the Christians.

In the 4th century, St. Helena, the mother of the Roman Emperor Constantine, went on a Holy Land pilgrimage to locate the important sites in Christianity. With the help of locals in the Holy Land, St. Helena located the spots of Jesus’ Birth, Crucifixion, and Resurrection. Today, the Church of the Nativity and the Church of the Holy Sepulchre mark these locations.

The Catholic Church does not have a specific teaching on when Jesus was born. There may be a “memory” of the early Christians being preserved in this date, or its significance is only symbolic. After Christianization of the empire, the Church often replaced pagan things (e.g. temples) with Christian ones (churches). Scholars disagree on the merit of such arguments in this particular case, however. For example, in his book, The Spirit of the Liturgy, writing as a theologian and not as pope, Pope Benedict XVI wrote,

The claim used to be made that December 25 developed in opposition to the Mithras myth, or as a Christian response to the cult of the unconquered sun promoted by Roman emperors in the third century in their efforts to establish a new imperial religion. However, these old theories can no longer be sustained.

SUMMARY OF THE QUESTION

Angels appeared to the shepherds to announce that Jesus was born (Luke 2:8-15). The deeper significance of shepherds visiting Jesus is that He is the Lamb of God and our Paschal sacrifice (the Lamb that is slaughtered at Passover). This indicates that, even from His Birth, He was meant to die for our sins, as the perfect sacrifice.

Who were the shepherds in Christ’s Nativity story?

They were unnamed, but they have a significant role in the Nativity story. Instead of appearing in front of kings, the Son of God was first made known to humble shepherds.

What did the angel say to the shepherds when Jesus was born?

The Gospel of Luke 2:10-14 says,

And the angel said to them, “Be not afraid; for behold, I bring you good news of a great joy which will come to all the people; for to you is born this day in the city of David a Savior, who is Christ the Lord. And this will be a sign for you: you will find a babe wrapped in swaddling cloths and lying in a manger.” And suddenly there was with the angel a multitude of the heavenly host praising God and saying, “Glory to God in the highest, and on earth peace among men with whom he is pleased!”

Scripture portrays the Messiah both as shepherd of souls and victim for souls. David was a shepherd boy when he was chosen to shepherd God’s people Israel as its king. Christ, his descendant, is the eternal shepherd of God’s redeemed people.

Scripture also portrays the Messiah as a lamb, who will be led to slaughter. This was foreshadowed in the Paschal Lamb of Exodus 12, and spoken of by Isaiah (Is. 53). In the Gospel of John and St. John’s epistles, Jesus is explicitly called the “Lamb of God.”

The Catechism of the Catholic Church (paragraph 608) says,

After agreeing to baptize him along with the sinners, John the Baptist looked at Jesus and pointed him out as the "Lamb of God, who takes away the sin of the world." By doing so, he reveals that Jesus is at the same time the suffering Servant who silently allows himself to be led to the slaughter and who bears the sin of the multitudes, and also the Paschal Lamb, the symbol of Israel's redemption at the first Passover. Christ's whole life expresses his mission: "to serve, and to give his life as a ransom for many."

Thus, it is fitting that the angels would revealed Christ’s birth to shepherds and they, in turn, would be among the first to acknowledge Him.

It is entirely possible that Jesus was born in a cave that was used as a stable. The hills of Judea are a soft stone, making for both natural caves and artificial ones. Houses would be built adjacent with the cave providing additional space, as well as warmth in winter and coolness in summer.

His being born in a cave truly speaks to the poverty that Jesus willingly entered. In his Midnight Mass homily in 1978, St. John Paul II said,

In order to have a complete picture of the reality of that event, in order to penetrate more deeply still into the realism of that moment and the realism of human hearts, let us remember that the event occurred precisely in the way it did: in abandonment and extreme poverty, in the cave stable outside the town, because people in the town refused to receive the Mother and Joseph into any of their homes. Nowhere was there room. From the beginning, the world showed itself inhospitable towards the God who was to be born as Man.

Why was Jesus born in a stable?

In a temporal sense, there was no room for St. Joseph and the Blessed Virgin at the inn. On a deeper level, however, Jesus’ humble birth highlights the fact that He sacrificed a great deal in order to become Man. Philippians 2:5-7 says,

Have this mind among yourselves, which was in Christ Jesus, who, though he was in the form of God, did not count equality with God a thing to be grasped, but emptied himself, taking the form of a servant, being born in the likeness of men.

In his apostolic letter Admirabile Signum (On the Meaning and Importance of the Nativity Scene), Pope Francis said,

Coming into this world, the Son of God was laid in the place where animals feed. Hay became the first bed of the One who would reveal himself as “the bread come down from heaven” (Jn 6:41). Saint Augustine, with other Church Fathers, was impressed by this symbolism: “Laid in a manger, he became our food” (Sermon 189, 4). Indeed, the nativity scene evokes a number of the mysteries of Jesus’ life and brings them close to our own daily lives.

Why was Jesus born into such humble circumstances?

The Catechism of the Catholic Church (paragraphs 525-526) says,

Jesus was born in a humble stable, into a poor family. Simple shepherds were the first witnesses to this event. In this poverty heaven's glory was made manifest. ...

To become a child in relation to God is the condition for entering the kingdom. For this, we must humble ourselves and become little. Even more: to become "children of God" we must be "born from above" or "born of God." Only when Christ is formed in us will the mystery of Christmas be fulfilled in us.

The word originates from the Latin word “nativitas” meaning “birth,” and is used by the Church as a formal title of this day and its celebration.

Why is the Nativity important?

God Himself became Man so that – through His death and Resurrection – we could then attain Heaven one day. When He entered into history, it was out of pure love for us.

In Admirabile Signum, Pope Francis said,

Why does the Christmas crèche arouse such wonder and move us so deeply? First, because it shows God’s tender love: the Creator of the universe lowered himself to take up our littleness. The gift of life, in all its mystery, becomes all the more wondrous as we realize that the Son of Mary is the source and sustenance of all life. In Jesus, the Father has given us a brother who comes to seek us out whenever we are confused or lost, a loyal friend ever at our side. He gave us his Son who forgives us and frees us from our sins.

According to St. Bonaventure’s book The Life of St. Francis of Assisi, the first Nativity scene was displayed in 1223 in the town of Greccio, Italy. St. Francis had recently made a pilgrimage to the Holy Land where he had seen the location of Our Lord’s birth. This inspired him to renew the faith of the people in Greccio who had allowed gift-giving to overtake the true meaning of Christmas. Instead of merely telling the parishioners about the Christmas story, Francis, a deacon, wanted to show it to them.

Pope Honorius III gave Francis permission to display a Nativity scene with hay, an ox and a donkey in a cave in Greccio. Bonaventure said, “Then [Francis] preached to the people around the Nativity of the poor King; and being unable to utter His Name for the tenderness of his love, he called Him the Babe of Bethlehem.”

Within 200 years, manger scenes had spread throughout Europe. The Italians continue this tradition with a particular fervor, with churches and towns making elaborate public nativities, and the Pope blessing the Bambinelli (Baby Jesus figures) on the Third Sunday of Advent. Children then place them in their family mangers when Christmas arrives.

Even though Jesus’ Name is never mentioned in the Old Testament, there are countless instances of Jesus being prophesied.

The Catechism of the Catholic Church (paragraph 522) says,

The coming of God's Son to earth is an event of such immensity that God willed to prepare for it over centuries. He makes everything converge on Christ: all the rituals and sacrifices, figures and symbols of the "First Covenant." He announces him through the mouths of the prophets who succeeded one another in Israel. Moreover, he awakens in the hearts of the pagans a dim expectation of this coming.

The Catechism of the Catholic Church (paragraphs 523-524) says,

St. John the Baptist is the Lord's immediate precursor or forerunner, sent to prepare his way. "Prophet of the Most High," John surpasses all the prophets, of whom he is the last. He inaugurates the Gospel, already from his mother's womb welcomes the coming of Christ, and rejoices in being "the friend of the bridegroom", whom he points out as "the Lamb of God, who takes away the sin of the world." Going before Jesus "in the spirit and power of Elijah", John bears witness to Christ in his preaching, by his Baptism of conversion, and through his martyrdom.

When the Church celebrates the liturgy of Advent each year, she makes present this ancient expectancy of the Messiah, for by sharing in the long preparation for the Savior's first coming, the faithful renew their ardent desire for his second coming. By celebrating the precursor's birth and martyrdom, the Church unites herself to his desire: "He must increase, but I must decrease."