Great you can answer the basic problem with Protestantism so you throw a theological hissy fit.
What external source verifies Scripture and on what authority does that external source operate?
The Truth the Word of God declares is foolishness to them who are perishing. You will not gender up an exception clause to ride the catholic dogma to salvation. God does the calling. God does the birthing. God raises up His children in the Way that they should go as His new borns.
You cannot strive to eventually obtain that which God offers immediately to those who will humble themselves and accept immediately the Grace of God in Christ.
Dogma will not lead you, cannot make God owe you.
Institutional trudgery will not take you to a place where God owes you something. When Jesus related that coming time where He says 'depart from Me I never knew you', He was giving a big hint that unless you are born again, born from above, you have not let Him know you.
His sermon to Nicodemus should be more than enough testimony, coming directly from God through His Scriptures, to inform anyone that Jesus has a plan and it is not based in your working for it. It is the Gift of God, the Grace of God in Christ Jesus.
Be ye transformed by the renewing of your mind. Do you know the two prongs of the way your mind is renewed?
I'll explain it if you tell me what it is.