This one is quite easy, if you've been brought up with Scriptures all your life.  God, our Heavenly Father, gave us His only Son, as a baby who grew into the Jesus we know.  We know:  John 3:16, "For God so loved the world, that He gave His only begotten Son, that whoever believes in Him shall not perish, but have eternal life."   John 6:40, "For this is the will of my Father, that everyone who looks on the Son and believes in him should have eternal life, and I will raise him up on the last day.”  And 1 John 4: 9-10, "In this the love of God was made manifest among us, that God sent his only Son into the world, so that we might live through him. In this is love, not that we have loved God but that he loved us and sent his Son to be the propitiation for our sins."   We celebrate the birth of our Little Lord Jesus... it's the way the story begins.