Christmas night tells each person, no matter how poor or sinful, that they are utterly and totally loved by God, Pope Francis said as he celebrated Jesus' birth.

The grace of God revealed in the birth of Jesus in a stable in Bethlehem "is divine love, the love that changes lives, renews history, liberates from evil, fills hearts with peace and joy," the Pope said in his homily as he celebrated the nighttime liturgy.

"Tonight, the love of God has been revealed to us: It is Jesus," he said.

The liturgy began with the "kalenda" or Christmas proclamation of Jesus' birth "innumerable ages" after the creation of the world, "in the year of the 194th Olympiad" and in the 42nd year of Caesar Augustus' reign when the whole world was at peace.