Everything we need to know for salvation is in the Bible. Many of the Catholic doctrines we Protestants disagree with were not made official for often hundreds of years after the furst century--howEVER were people in the church saved before that happened? However did they survive without them?Which is why as a Roman Catholic I do not make the argument that not everything Jesus said or did is in the Scriptures.
I believe that all Christian Truth is contained either implicitly or explicitly in the Scriptures. I believe that the Scriptures are the supreme authority in the Church.
My position is different from the Protestant in three ways:
1) That ONLY the Scriptures are infallible. I believe ONLY the Scriptures are God Breathed, but not ONLY Scripture is infallible. The Protestant in my mind jumps to conclusions when the Protestant tries to argue that because only the Scriptures are God Breathed it means only the Scriptures are infallible. Show from Scripture where Scripture teaches that ONLY that which is God Breathed is infallible.
2) Scripture is the supreme manifestation of God's authority in the Church but not the sole locus of God's authority in the Church. Lesser manifestations of God's authority are in Church councils and when the Church defines doctrine and Tradition. Here also, the Protestant jumps to conclusions. The Protestant seems to jump from "Only Scripture is God Breathed" to "Therefore ONLY Scripture speaks with God's authority or is the locus of God's authority
3) Catholics do not believe that the certainty of the Christian Faith is derived from the Scriptures alone. Catholics believe that Tradition is also another mechanism by which the one and the same Gospel handed on in the Scriptures is preserved. Tradition is infallible, but not God Breathed. The authority of the Church is infallible, but not God Breathed.