Sicut erat in princípio et nunc et semper, et in sǽcula sæculórum.
As it was in the beginning, and now, and always, and in the ages of the ages.
This is the end of the doxology. We recite the doxology at least 25 times daily in the Ordinary Form breviary, not counting the doxologies of hymns. Our common English translation is “as it was in the beginning, is now, and ever shall be, world without end.” The translation we use in the breviary is “As it was in the beginning, is now, and will be forever.” A literal translation is given above.
Sicut = As, just as. As in, Forgive us our trespasses as we forgive those who trespass against us (sicut et nos dimittimus debitoribus nostris).
Semper = Always. This is an adverb. The Marines say “Semper Fi”, short for “Semper Fidelis”, always faithful. Glory to God, always.
Nunc = now.
A saeculum (noun, neuter) is a measure of time: an age, a generation, a century. “In saecula” means into the ages. Saeculorum is in the plural genitive case, which translates “of the ages.” “The ages of the ages” is a symbolic phrase meaning something like always. Think of Buzz Lightyear’s catchphrase, “To infinity, and beyond!” In saecula saeculorum.
How would you say “He was in the beginning with God”? = Erat in principio apud Deum.
How would you say “He is always with us?” = Est semper nobiscum.