Galatians 4:4-7; In his letter to the Galatian church, the Apostle Paul outlines the foundational basis for Christians to celebrate Christmas. While elaborating upon the nature of being an heir under the Mosaic law, he notes that “God sent his Son” at the precise time in human history for the purpose of making believers into sons and heirs of God. While the manger in Bethlehem is important as a starting point for the Incarnation, the ministry work of Jesus Christ is the heart of this special holiday.