‘We were once in darkness, in a kind of night, which was to be diminished by the growth of faith; that’s why, on the day we celebrate the birth of our Lord Jesus Christ, the night begins to be encroached upon, and the day to grow longer. So, brothers and sisters, let us keep this day as a festival; not, like the unbelievers, because of that sun up there in the sky, but because of the one who made that sun.’

– Augustine, Sermon 190. 395 A.D

Source:

Augustine, Saint; Doyle, D & Hill, E  Essential Sermons New City Press. Kindle Ed. (p. 251).