The Catholic Church has made it a requirement to belong to that church. That IS part of their salvation plan. Shall we simply consider those who teach that to be accursed of God then since you can't show the apostles taught it? It's looking that way.
“Jesus said to them again, ‘Peace be with you. As the Father has sent me, even so I send you.’ And when he had said this, he breathed on them, and said to them, ‘Receive the Holy Spirit. If you forgive the sins of any, they are forgiven; if you retain the sins of any, they are retained.’ “
Why do you pretend to understand Catholicism when you clearly do not?