To Catholics, my question is, how can salvation be limited to Catholics only, when Scripture—which Catholics do reverence—appears to go against that belief? To non-Catholics, how do you feel about a Protestant's converting to Catholicism?
She got plenty of answers, and planned on responding to them. But:
Now that I've had time to think about it, I'm sorry that I can't really say anything more than I said at the first. I still read the Scripture that I cited the same way I read it before—that faith in Jesus is what's necessary for salvation, and that such faith does not have to be mediated through a church. I do believe that church should play a central part in the believer's spiritual life—there's certainly plenty of Scripture to back that up—but the one and only true mediator is Jesus Christ.
And you know what? I agree with this.
So does the Catechism of the Catholic Church, in which the word "mediator" appears twelve times, each time in reference to Christ. It is prefaced by such words as "the one" (5 times), "unique" (2), "only" (2), and "one and only" (once). Another paragraph reads:
Jesus Christ, having entered the sanctuary of heaven once and for all, intercedes constantly for us as the mediator who assures us of the permanent outpouring of the Holy Spirit.
How are we to understand this affirmation, often repeated by the Church Fathers? Re-formulated positively, it means that all salvation comes from Christ the Head through the Church which is his Body:
Basing itself on Scripture and Tradition, the Council teaches that the Church, a pilgrim now on earth, is necessary for salvation: the one Christ is the mediator and the way of salvation; he is present to us in his body which is the Church. He himself explicitly asserted the necessity of faith and Baptism, and thereby affirmed at the same time the necessity of the Church which men enter through Baptism as through a door. Hence they could not be saved who, knowing that the Catholic Church was founded as necessary by God through Christ, would refuse either to enter it or to remain in it.
The interior quotation is from Lumen Gentium 14. It neatly expresses the Catholic doctrine that Jesus is the one Mediator and the Church is necessary for salvation.
Why? Because Christ's Body is the Church. Faith in Christ does not have to be mediated through "a church," but salvation does come only through the Church, which is to say through Christ's Body.
When Saul of Tarsus was knocked to the ground on the road to Damascus, he heard a Voice say, "Saul, Saul, why are you persecuting me? ... I am Jesus, whom you are persecuting."
Jesus didn't ask Saul why he was persecuting His disciples, or even His church. It was Jesus Himself whom Saul was persecuting.
So, while it is of course possible to distinguish between Jesus and the Church, it is impossible to separate them. What God has joined together, let no man put asunder.