That's what comes of being one's own Pope and proclaiming one's own salvation. Individuals have the best chance of getting it wrong at some point. It is the Church that is the pillar and foundation of truth, not some apostate in his cups deriving new truths with every gulp.
Jesus is the rock on which the church, His body comprised of believers throughout the ages, is built.
1 Corinthians 1:11-17 11For it has been reported to me by Chloe’s people that there is quarreling among you, my brothers. 12What I mean is that each one of you says, "I follow Paul," or "I follow Apollos," or "I follow Cephas," or "I follow Christ." 13 Is Christ divided? Was Paul crucified for you? Or were you baptized in the name of Paul? 14I thank God that I baptized none of you except Crispus and Gaius, 15so that no one may say that you were baptized in my name. 16(I did baptize also the household of Stephanas. Beyond that, I do not know whether I baptized anyone else.) 17For Christ did not send me to baptize but to preach the gospel, and not with words of eloquent wisdom, lest the cross of Christ be emptied of its power.
1 Corinthians:3:1-17 1But I, brothers, could not address you as spiritual people, but as people of the flesh, as infants in Christ. 2 I fed you with milk, not solid food, for you were not ready for it. And even now you are not yet ready, 3for you are still of the flesh. For while there is jealousy and strife among you, are you not of the flesh and behaving only in a human way? 4For when one says, "I follow Paul," and another, "I follow Apollos," are you not being merely human?
5What then is Apollos? What is Paul? Servants through whom you believed, as the Lord assigned to each. 6 I planted, Apollos watered, but God gave the growth. 7So neither he who plants nor he who waters is anything, but only God who gives the growth. 8He who plants and he who waters are one, and each will receive his wages according to his labor. 9For we are God’s fellow workers. You are God’s field, God’s building.
10 According to the grace of God given to me, like a skilled master builder I laid a foundation, and someone else is building upon it. Let each one take care how he builds upon it. 11For no one can lay a foundation other than that which is laid, which is Jesus Christ. 12Now if anyone builds on the foundation with gold, silver, precious stones, wood, hay, straw— 13 each one’s work will become manifest, for the Day will disclose it, because it will be revealed by fire, and the fire will test what sort of work each one has done. 14If the work that anyone has built on the foundation survives, he will receive a reward. 15If anyone’s work is burned up, he will suffer loss, though he himself will be saved, but only as through fire.
16 Do you not know that you are God’s temple and that God’s Spirit dwells in you? 17If anyone destroys God’s temple, God will destroy him. For God’s temple is holy, and you are that temple.