In the second chapter of Luke you read the story of the birth of Jesus Christ. Jesus means:God saves. Christ means: Anointed One, Messiah, Lord.
The eternal Son of God left heaven to be born as a human being. And then also in extremely humble circumstances: a manger is His cradle. His birth was but the first stage of His humiliation; then His suffering, death and burial would follow. The purpose of this humiliation was to give Himself to vicariously bear the penalty for the sins of men, and thus bring about reconciliation with God. Reconciliation with God is for those who believe in this 'Lamb of God' (John 1 verse 29)
Shepherds hear the glad tidings through an angel that the Savior has been born. They believe the angel's words and come to worship Jesus.
Old Testament prophecies fulfilled:
At Bethlehem the shepherds kept watch over their flocks on the night when Jesus was born.
Bethlehem, the birthplace of Shepherd King David, is where the great Son of David, the Good Shepherd - see John 10 verse 11- is born, as prophesied:
But you, Bethlehem Ephrathah, though you are small among the clans of Judah, out of you will come for Me One who will be Ruler over Israel, whose origins are from of old, from ancient times.
Micah 5 verse 2.
Ezekiel 34 verse 15 and 16:
I myself will tend My sheep and have them lie down, declares the Sovereign Lord.
I will search for the lost and bring back the strays. I will bind up the injured and strengthen the weak, but the sleek and the strong I will destroy. I will shepherd the flock with justice.
Isaiah 40 verse 11:
He tends His flock like a shepherd: He gathers the lambs in His arms and carries them close to His heart; He gently leads those that have young.
Isaiah 9 verse 2:
The people walking in darkness have seen a great light; on those living in the land of deep darkness a light has dawned.
Malachi 4 verse 2:
But for you who revere My Name, the sun of righteousness will rise with healing in its rays. And you will go out and frolic like well-fed calves.