Consider the thread of paul's reasoning in Rom. 9-10"
Rom. 9:1-3 - Paul is in anguish and sorrow for his fellow Jews, so much so that if himself being accursed would help them be saved, he would wish it.
Rom. 10:1-4 - Paul prays for his fellow jews that they may be saved, because they are depending on their righteousness to save them and not submitting to God's righteousness that comes through christ.
Rom 10: 9-10 - Belief is not only what leads to being "saved" but "justified."!
Rom. 10: 14-15 - Paul shows that people need to go and tell the good news.
If all of this is speaking of ONLY temporal salvation, we have a few hard questions:
1. Why get so worked up "in anguish" and "sorrow" if they are actually elect and will be ultimately saved whether they believe or not. (remember it is the PB view that since they were pursuing righteousness, however incorrectly, it is evidence of their regeneration, even if they rejected Jesus).
2. Is Rom. 10:10 speaking of a "timely" or temporal "justification"? Because Justification in Romans seems to be related to our state before God that determines our eternal acceptance by him.