"the festive day on which he who is the great and eternal day came from the great and endless day of eternity into our own short day of time"

"Let us . . . joyfully celebrate the coming of our salvation and redemption.  Let us celebrate the festive day on which he who is the great and eternal day came from the great and endless day of eternity into our own short day of time."

"Celebremus laeti nostrae salutis et redemptionis adventum.  Celebremus festum diem, quo magnus et aeternus dies ex magno et aeterno die venit in hunc nostrum tam brevem temporalem diem."

     St. Augustine, Sermon 185.2 on the Nativity (25 December 412/416), as translated in the Office of readings for 24 December, Liturgy of the hours.  Latin from PL 38, col. 998 (997-999).  Clearly no difference in the Latin between "eternal" and "endless."  "festal" vs. "great and "eternal" vs. ever "so brief [and] temporal."