Read Genesis 12:1-3, 15:1-7 Key verse Gen. 1:3b "All the families of the earth will be blessed through you."
"How can this be?"
The question of Christmas is answered first of all by the fact that God cares about us. In the first pages of the Bible we see how the human race messed up, big time. The first humans disobeyed the only rule God gave them. Their first child killed his younger brother. Violence filled the earth. God saved the only people worth salvaging from a great flood. Their descendents tried to be their own gods(Gen. 11). The world was in a mess. But God started a long process to bring the human race back to Himself.
This reclamation project started with a man named Abram who would become Abraham. In spite of the human condition the Lord was going to use a man. It would be God who saved us, but He would use humans in a long process that would lead to the Lord Himself becoming a man. Why God chose Abram and ultimately his descendents to be line for the Christmas event is a question which only the Lord Himself knows the answer. But we can certainly surmise that it was out of His own goodness and greatness that the Lord chose Abram and chooses us.
There is a Dennis the Menace cartoon in which Dennis and a friend are eating cookies baked by Mrs. Wilson. The friend comments to Dennis that he must be awfully good for Mrs. Wilson to bake him such good goodies. Dennis astutely remarks that Mrs. Wilson made him the cookies, not because he is so good, but because Mrs. Wilson is so good. God loves us and saves us, not based on our goodness but His.
Your world may be a mess. But Christ came into our world to fix it and to fix us. He will come to everyone who will receive Him and be a blessing. Dennis had to eat the cookies to enjoy it and we must have faith in Christ to enjoy His salvation. You may be a saved person in a terrible mess. You can never be so far away from God that He can't help you. No problem is too big for Him. He said to Mary, "Nothing is impossible with God" This Advent season gives us hope because we know that God cares. He proved it beginning with Adam, Eve, Abraham and many others, completing it in Christ. He will come into every heart that opens up to Him and lets Him in (Rev. 3:20). A good Christmas prayer is, "O holy child of Bethlehem! Descend to us, we pray; Cast out our sin and enter in, be born in us today."