Sunday’s Collect for the Ordinary Form was not in a previous edition of the Roman Missal. A precedent is found in the Sacramentarium Bergomense.
Omnipotens sempiterne Deus,
semper in nobis paschale perfice sacramentum
ut, quos sacro baptismate dignatus es renovare,
sub tuae protectionis auxilio multos fructus afferant,
et ad aeternae vitae gaudia pervenire concedas.
Almighty eternal God,
perfect in us always the paschal mystery,
so that those whom You deigned to renew by means of sacred baptism,
may under the aid of Your protection bear many fruits,
and that You will grant them to attain unto the joys of eternal life.
OBSOLETE ICEL (1973):
may we whom you renew in baptism
bear witness to our faith by the way we live.
By the suffering, death, and resurrection of your Son
may we come to eternal joy.
CURRENT ICEL (2011):
Almighty ever-living God,
constantly accomplish the Paschal Mystery within us,
that those you were pleased to make new in Holy Baptism
may, under your protective care, bear much fruit
and come to the joys of life eternal.
Perfice as the imperative “perfect” has the force of “bring to completion”. It could be perceived as “perfect” in an instant of time, by a sudden and all embracing act, or it could be construed as being an ongoing process of perfection, of bringing to completion. In a way the Paschale Mystery itself (remember that mysterium and sacramentum are pretty much interchangeable in these contexts) reflects this same problem of our perception of time and God’s work in time, or outside of time, or beyond time. The Paschal Mystery is both completed and not completed. Our redemption is “already” completed, but “not yet” completed. As Christians we live in this pilgrim life, this earthly continuum, in a constant state of “already but not yet”.
We have some time to look at the word sempiterne.
This is a vocative form of sempiternus, a, um. In philosophy and theology (mostly indistinguishable in ancient times through late antiquity) there has been constant effort to figure out time and God’s relationship to time. In this prayer sempiternus is simply the equivalent of aeternus, “eternal”. Scripture has innumerable references to God being aeternus and it is associated with God’s unchanging nature. There are some 50 or so prayers in the Ordinary Form missal which begin with today’s formula and many that start with aeterne Deus.
Even though the words are pretty much interchangeable in our prayers, eternity and sempiternity are really different concepts.
Eternity can be thought of different ways.
First, eternity can be completely independent of time. Something eternal in this sense is entirely outside of time. St. Augustine, who was a Neoplatonist in this sense, thought of God this way.
Another eternity is everlastingness. It has no beginning or end. This is what we call sempiternity. That is to say, it exists at “all points in time”.
This is a great simplification of a millennial discussion, but it can give you a quick glimpse into this language of prayer.
The Greeks, from Parmeides to Plato to Plotinus all wrote about eternity. Christian ideas of eternity were explored by authors like St. Augustine (+430), Boethius (+c.526), Eriugena (+c.877), St. Anselm (+1109), St. Thomas Aquinas (+1274).
When we say in these prayers that God is sempiternus we do not thereby believe as Catholics that God is “everlasting” in the sense of being in time, that is all points of time, but without beginning or end. God is eternal in the sense of being beyond time, entirely transcending time.
Finally, there is in this prayer a reference to John 15:16:
“Non vos me elegistis sed ego elegi vos et posui vos ut eatis et fructum adferatis et fructus vester maneat ut quodcumque petieritis Patrem in nomine meo det vobis… You have not chosen me: but I have chosen you; and have appointed you, that you should go and should bring forth fruit; and your fruit should remain: that whatsoever you shall ask of the Father in my name, he may give it you.”
By the way, in the 1970 editio typica of the Missale Romanum the Collect is:
Deus, per quem nobis et redemptio venit et praestatur adoptio,
filios dilectionis tuae benignus intende,
ut in Christo credentibus
et vera tribuatur libertas et hereditas aeterna.
In other words, the Collect was changed for the 2002 edition.