“It is true exegesis, not eisegesis, to say that the nativity of Christ is the nativity of the Christian; Christmas day is the birthday of every Christian”
(Karl Barth, Church Dogmatics, IV/4: 15). 

What does Barth mean by this extraordinary statement? The Christian is one whose entire existence is grounded in the life and history of Jesus Christ. He is the Representative of all humanity, of each and every person. He was born, lived, died and was raised again for them, in their name and in their stead. As the Messiah and Saviour of all, Jesus entered into solidarity with us, identifying himself with us to the extent that his baptism includes within itself that of his disciples. So, too, his death includes within itself our death also, so that we die in him and with him.

Jesus does not drink that cup for Himself alone. He is not baptised with that baptism in isolation. This all takes place in their stead and for them. Hence they, too, will die in His death, and therewith their entry into glory will be secured (16). 

“In his death, therefore, He took the place of all….Inasmuch as He died the death in our place, we have it absolutely behind us. In His death we who deserved to die as He died are already put to death” (16).

His birth, life and death is our birth, life and death. His resurrection is our resurrection.
He is our Christmas, the wonder, mystery and miracle of grace.
Happy Christmas!