But this is said against those who judge others' salvation and act pridefully at that. This is a good advice, but it is not a doctrinal statement about scripture alone is the rule of faith. I can say to my fellow Catholics the same thing: When you argue with the Protestants, prove the error of Protestantism from scripture.
Hebrews 4: 12 For the word of God is alive and active. Sharper than any double-edged sword, it penetrates even to dividing soul and spirit, joints and marrow
This is praise of the Holy Scripture and a Catholic teaching as well. It does not say that the Scripture is the sole rule of faith, just that it is a very good rule. We all agree on that.
Romans 1: 16 For I am not ashamed of the gospel...
Of course. It is the gospel that condemns Protestantism most squarely. Sole Scriptura does not follow from this verse either, though.
Romans 3: 23 for all have sinned and fall short of the glory of God, 24 and all are justified freely by his grace through the redemption that came by Christ Jesus
This teaches salvation by grace alone, not by faith alone. The former is Catholic teaching; the latter -- gross scriptural error.
However, I can prove from Scripture that the Church is the complete rule of faith. That is because it is written: "whatsoever thou shalt bind upon earth, it shall be bound also in heaven: and whatsoever thou shalt loose upon earth, it shall be loosed also in heaven" (Matthew 16:190, and another time: "tell the church. And if he will not hear the church, let him be to thee as the heathen and publican. Amen I say to you, whatsoever you shall bind upon earth, shall be bound also in heaven; and whatsoever you shall loose upon earth, shall be loosed also in heaven." (Matthew 18:17-18). Both time the power to bind and loose is given to people guided by the Holy Ghost, not to books, and that power is absolute as it operates in heaven.
Thou hast almost been persuaded to become a PROTESTant!