The central message of this sermon is that God has graciously included every person, regardless of their background or circumstances, on His Christmas list, giving them the gift of salvation through His Son Jesus Christ. This idea advances the belief in the universal nature of God's love and redemption, which was a revolutionary concept at the time of the original audience (Jews) but is still relevant today. The sermon highlights that God's redemptive work is not limited to the Jewish people, but extends to all nations and peoples on earth. The takeaway the teacher wants the listener to understand is that they are recipients of God's gracious gift of salvation, which is just the beginning of His giving.