In saecula saeculorum
The Latin phrase in saecula saeculorum expresses the idea of eternity and is literally translated as "in a century of centuries." It is biblical, taken from the Vulgate translation of the New Testament, translating the Greek phrase "εἰς τοὺς αἰῶνας τῶν αἰώνων" (eis toùs aionas ton aiṓnōn).