Read Luke 1:5-25,39-45 Key verse: "When Elizabeth heard Mary's greeting, the baby leaped in her womb, and Elizabeth was filled with the Holy Spirit." (Lk. 1:41)
How can this be?
God is in the life-giving business. Mary wondered how God could work a miracle in her life even as she prepared to visit her cousin, Elizabeth, who herself was blessed with the miracle of a child. Elizabeth, like Hannah, had been barren but now was pregnant with a baby that would grow up to be John the Baptist, the forerunner of Christ. Even in his the womb John sensed he was in the presence of Divinity when Mary came to visit his mother.. He leaped for joy and Elizabeth was filled with the Holy Spirit. God can become a man because He is a life-giver. That's what He does.
When we are carrying the Life of God in us, others can sense it. They may not be able to put their finger on what they are feeling, but it can cause them to jump for joy. They will want what we have. In my late twenties I made some friends that had the joy of the LORD. I did not understand all the theology or even agree with it, but they had something I wanted. They had life and I did not. My encounter with them ultimately caused me to ask for God's life in me through the Holy Spirit. I still cannot explain how it can be, but I know god has placed his life in my heart.
I have learned over the years that "God is light and in Him is no darkness at all." John the Apostle wrote this light is the life we all need and are looking for. Christmas is a time of life. A new life coming to a feeding trough in Bethlehem. And He changed the world! The leap of joy you will feel, will cause you to begin the wonderful experience of being filled with His Spirit.