Did the Immaculate Conception of the Blessed Virgin Mary occur by virtue of the foreseen merits of Jesus Christ? No, not really. Many authors make this type of assertion. But the actual text of the dogma says “in view of the merits of Jesus Christ”. And I can find no magisterial documents even using the phrase “foreseen merits” in any context.
What is the difference?
First, God does not foresee the future. God is not stuck in today, remembering yesterday and looking ahead to tomorrow. God is unbounded by time. “To God, all moments of time are present in their immediacy.” (CCC 600). God’s knowledge of all things is comprised in a single act. God does not think about a subject, remember a past event, foresee a future event, and then reach a conclusion. All that God knows, all that God does, all that God is by His very Nature, is one Act, and that Act is entirely the same as the Divine Nature. So the power of God to know the future far exceeds any ability to “foresee” future events.
Second, Jesus obtained our salvation by His suffering and death on the Cross, and by His Resurrection from the dead. But the merits of Christ’s salvific deeds are not merely foreseen. They are applied by God without any restriction of place or time whatsoever, for God is all-powerful. He is able to apply the graces won for us on the Cross directly and fully, at any time, in any place. The graces obtained for us by Christ on the Cross are applied to created persons, past, present, and future, not as something merely anticipated or remembered, but just as immediately as if we were each and all continually at the foot of the Cross, next to the Blessed Virgin Mary.
Now, we could use the term “foreseen merits” as something of an anthropomorphic expression of God’s infallible knowledge of all things, including the future. But it is an inaccurate term, and it is not found in the dogmatic definition of the Immaculate Conception.
Declaramus, pronuntiamus et definimus doctrinam quae tenet beatissimam Virginem Mariam in primo instanti suae conceptionis fuisse singulari Omnipotentis Dei gratia et privilegio, intuitu meritorum Christi Jesu Salvatoris humani generis, ab omni originalis culpae labe praeservatam immunem, esse a Deo revelatam, atque idcirco ab omnibus fidelibus firmiter constanterque credendam.
We declare, pronounce, and define that the doctrine, which holds that the most Blessed Virgin Mary, in the first instant of her conception, by a singular grace and privilege of Almighty God, in view of the merits of Jesus Christ, the Savior of the human race, was preserved immune from every stain of original sin, is revealed by God, and therefore is to be believed firmly and constantly by all the faithful. (Pope Pius XI, Ineffabilis Deus).