Obsequium religiosum.
What exactly is the difference between it and the full assent of faith given to the infallible Magesterium?
Hello Yab Yum,
Well, technically, one does not give the full assent of faith to the infallible magisterium. Instead, such assent is given to that which is defined, by that magisterium, as part of divine revelation.
One can say, in answer to your question, that there is a difference in the subject and object.
The object of religious submission is not part of the deposit of the faith. The teachings we are to submit to “are set forth in order to arrive at a deeper understanding of revelation, or to recall the conformity of a teaching with the truths of faith, or last to warn against ideas incompatible with these truths or against dangerous opinions that can lead to error” (Ratzinger, Commentary on the Profession of Faith, June 29, 1998). On the other hand, the object of what we believe with divine and catholic faith is what has been revealed by God.
It is different in the subject because the virtue of faith, while it involves the intellect and will, is not the same as religious submission of the intellect and will. Faith was called “the full obedience of intelligence and will” in Vatican I (Dei Filius, ch. 6). St. Paul said the faithful should respond to revelation by "bringing every thought into captivity to the obedience of Christ (2. Cor. 10: 5-6).
So, it is the difference between the full obedience that is “faith” and religious submission. Externally, there might not be an observable difference between these two responses. Internally, there is. Compare “I believe it.” to “I religiously accept and submit to it.”
Just a few thoughts…
Dan