The Emperor Constantine with the Bishops of the 1st Council of Nicaea (325), holding the Nicene–Constantinopolitan Creed of 381
One of the common objections to the notion of an unconditional Incarnation is the phrase from the Nicene-Constantinople Creed: “For us men and for our salvation He came down from Heaven…” On the surface it appears to be stating that the motive of the Incarnation is for the salvation of mankind. Since this is from the Councils of the Church one would cease to be a Catholic and begin to be a heretic by not embracing this revealed truth.
There are at least two ways that the Creed can be seen as coherent with the Franciscan thesis of the absolute primacy of Christ. The first is by following along the lines of St. Irenaeus, namely, that the term “salvation” is not restricted to redeeming man from sin, but is a much broader term which includes man’s salvation from sin, viz. Redemption. Salvation comes by justification through faith in Jesus – St. Paul repeats this tirelessly in his Epistles – and this justification makes us children of God, that is, it elevates us from the natural plane (creatures) to a supernatural plane (children of God). I maintain that this economy of grace is the economy of grace established by God from the beginning for Angels and Saints and that this economy is not contingent upon sin. Fr. Alessandro M. Apollonio, FI, explains this more in depth (see here) and I have also dealt with this topic in commenting on Eph. 1:7.
The second way that our Profession “for us men and for our salvation” can be seen as not only coherent, but even affirming the absolute primacy of Christ is by seeing this as two distinct motives: Christ came 1) for us men AND 2) for our salvation. In this case salvation would be equivalent to Redemption. Christ comes for us men – to bring us into the divine life of grace as adopted children; because of Adam’s sin, Christ also comes for our salvation – to repair the fall and restore us to divine grace. There is a concise explanation of this by a blogger named “Johannes”. In response to the question, “Does Catholic doctrine teach that the Incarnation would have taken place regardless of Adam’s decision?” (original post is here) he writes:
…the open status of the issue within Catholic doctrinal orthodoxy is clear at the beginning of St. Thomas Aquinas’ answer to the corresponding question in his Summa Theologica (ST III, q.1, a.3), by the way he describes his position:
I answer that, There are different opinions about this question. For some say that even if man had not sinned, the Son of Man would have become incarnate. Others assert the contrary, and seemingly our assent ought rather to be given to this opinion.
Notably, a most authoritative text that is compatible with the position of “unconditional Incarnation” of the Son when rightly understood is the Nicene creed, where we profess that:
For us men and for our salvation He came down from heaven, and by the Holy Spirit was incarnate of the Virgin Mary, and became man.
Salvation, in Roman Catholic and Eastern Orthodox theologies, does not carry a purely negative meaning of taking out sin, but also, and most importantly, a positive meaning of making men “partakers of the divine nature” (2 Pe 1:4), a notion the Greek call “theosis”. Though RCs and EOs differ in the way this is achieved (whether by sanctifying grace and charity or by the divine energies), they agree that it implies the elevation of human nature to a super-natural plane (= above the purely natural plane) and that it is a divine work different from the creation of human nature.
Just as the Incarnation was not strictly necessary for God to forgive men’s sins, but was the most fitting way to do it, neither was the Incarnation strictly necessary for God to make men partakers of the divine nature even in the absence of sin, yet, IMO, it was the most fitting way to do it.
Therefore, with “salvation” understood in its positive sense, unconditional Incarnation is wholly compatible with the Son becoming man “for us men and for our salvation”, even if Adam had not sinned.