Now the birth of Jesus Christ was as follows: After His mother Mary was betrothed to Joseph, before they came together, she was found with child of the Holy Spirit.
Matthew 1:18 NKJV
Excuse me? Pregnant? Who is responsible for it? Holy Spirit! So this is Christians? Joseph had nothing to rejoice about, but to accept his lot, and pose as the father of Jesus, to protect him from from harm, in order to fulfill Scripture (Matthew 1:22-23). Christmas is about fulfilling Scripture and it's not a pleasant thing but the Most Rewarding Thing!