We may surmise this because of what Paul wrote in Galatians: "Galatians 2:2 And I went up by revelation, and communicated unto them that gospel which I preach among the Gentiles, but privately to them which were of reputation, lest by any means I should run, or had run, in vain."
Further, we may apply the body of his other teaching and see the consistency of addressing the security of the believer, as in his passing reference, "Colossians 1:13 Who hath delivered us from the power of darkness, and hath translated us into the kingdom of his dear Son:" and "1Thess 1:9For they themselves relate of us, what manner of entering in we had unto you; and how you turned to God from idols, to serve the living and true God. 10And to wait for his Son from heaven (whom he raised up from the dead,) Jesus, who hath delivered us from the wrath to come."
It’s apparently a very Catholic error to take the words “work out” and remove them completely from the context of Paul, Apostle to the Gentiles, as well as the Pauline Epistles which are not works-based in the least. Such belief also ignores not just the acknowledged English meaning of the words contained in practically every English translation of the Bible including the 18th century Challoner Revision Douay-Rheims, but the meaning in the original Greek.
I don’t quite understand how such a clumsy and blatant misunderstanding becomes current in a church that so greatly prides itself on being guided by a group of learned elders going back millennia, but there it sits. I wonder if it’s an official church teaching, in which case I’d be totally mystified, or a popular misunderstanding that has been promulgated for the usual reason, i.e. it gives even greater power to the priesthood?
>>Further, we may apply the body of his other teaching and see the consistency of addressing the security of the believer
So is it your opinion that those who “backslide”, and by their thoughts and deeds live contrary to the teachings of God, are still saved anyway? And speaking of “the believer” what exactly is it that must be believed? Doesn’t is say in the Bible that even Satan believes? Is he also saved?