Bethlehem is the place associated with Jesus’ infancy because He was born there.
See Matthew 2:1, After Jesus was born in Bethlehem in Judea, during the time of King Herod, Magi from the east came to Jerusalem.
In the Gospels there are two genealogies of Jesus. One is of Mary, Jesus’ real mother ;the other is of Joseph, Jesus legal guardian. (Matthew and Luke)
In Matthew, the one which belongs to Joseph, Jesus’ legal guardian. Read Matthew 1:17–19, Thus there were fourteen generations in all from Abraham to David, fourteen from David to the exile to Babylon, and fourteen from the exile to the Christ. This is how the birth of Jesus Christ came about: His mother Mary was pledged to be married to Joseph, but before they came together, she was found to be with child through the Holy Spirit. Because Joseph her husband was a righteous man and did not want to expose her to public disgrace, he had in mind to divorce her quietly.
We can see that it is the basis of our faith in Christ as our Savior. Only someone who has both a divine and a human nature can live a perfect human life, and take on himself the punishment of all man’s (human) sin. Christ is the only one who can take away our sin, and bring us to God.
For centuries God had spoken through His messengers, the prophets. God had promised the coming of the special King, also called the "Messiah" or "Christ" This King would rule over the wonderful Kingdom of God. Then Jesus arrived and said, in effect "The long wait is over."
Jesus calls His message "the Good News" or "Gospel" See Micah 5:2, 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. See also Isaiah 9:6, For to us a child is born, to us a Son is given, and the government will be on His shoulders. And He will be called Wonderful Counselor, Mighty God, Everlasting Father, Prince of Peace.
Bethlehem is a little village near Jerusalem. Centuries earlier, it was the home town of David, King of Israel and descendant of Judah.
Think about it. Did you choose your parents or birthplace? How could anyone predict such details far in advance ? Yet Jesus the King was born in Bethlehem. They tell of the family line that would lead to the greatest King of all. They tell of His birth, His work, His teaching, His death and more. Indeed, the Bible gives the fulfillment of prophecy as a way for us to recognize God’s work.
Jesus is the only one who can save us. An angel can’t save us; Mary can’t save us. Not even God the Father, or God the Holy Spirit without Christ can save us. Only Jesus has the two natures that can bring us to God. Because He is the only being in the whole universe who has two natures, one human and the other divine, and so can bridge the gap between sinful people and God.
Read John 1:12–13, Yet to all who received Him, to those who believed in His name, He gave the right to become children of God–children born not of natural descent, nor of human decision or a husband’s will, but born of God. Read also John 3:6–7, Flesh gives birth to flesh, but the Spirit gives birth to spirit. You should not be surprised at my saying, You must be born again.
These verses clearly teach us that people become sons of God by being born again by the Holy Spirit.
So all those who have been born again by the Holy Spirit are sons of God in this special sense. However, as we have seen, only Jesus is Son of God in a unique sense because He is the only person who from His birth had a divine as a human nature. See Matthew 16:16, Simon Peter answered, You are the Christ, the Son of the living God. See also Galatians 4:4–7, But when the time had fully come, God sent His Son, born of a woman, born under law, to redeem those under law, that we might receive the full rights of sons. Because you are sons, God sent the Spirit of His Son into our hearts, the Spirit who calls out, Abba, Father. So you are no longer a slave, but a son; and since you are a son, God has made you also an heir.