The mentality of many Catholics seems to leave people with the impression that no one is given the gift of hearing God speak to them through the Scriptures. This puts a bad taste in the mouths of someone who takes up the written Word and is moved to conversion of heart and hungry to learn about the Lord.
Even in the 12 passages that were interpreted infallibly by the Church, the Church has acknowleged various meanings that can be seen in them.
CCC #133
The Church "forcefully and specifically exhorts all the Christian faithful… to learn ‘the surpassing knowledge of Jesus Christ,’ by frequent reading of the divine Scriptures. ‘Ignorance of the Scriptures is ignorance of Christ.’ "
This quote from paragraph 133 doesn’t deny the Magisterium’s authority nor that of Sacred Tradition, but calls for reading of Scripture so that a Catholic is not ignorant of why the Church is the Body of Christ and where they encounter Him personally in all his Grace and Truth and Authority.
The Ethiopian eunuch was not encouraged by Philip to read Isaiah and to interpret it himself and figure out Christ himself and start a church based upon his interpretation. Philip was glad he was reading Isaiah and Philip was glad to give him the true interpretation of Scripture with Authority and Spirit granted by Christ to the Apostles to know and explain the Truth and Grant participation in Christ personally in Baptism (a participation one cannot have simply by reading and privately interpreting Scripture).
The Church is literally Jesus, walking to Emmaus with the person reading the Scriptures, and their hearts burn within them as they walk together and the reader listens to the Church opening to them the meaning of what they are reading, that it was " ‘necessary that the Christ should suffer these things and enter into his glory?’ And beginning with Moses and all the Prophets, he interpreted to them in all the Scriptures the things concerning himself."
Scripture is an “instrument” or “tool” of the Church, and not a stand alone self-interpreting miracle that suddenly appeared from God on a bookstore shelf, but was written by and is carried by the Church as its tool for witness of the reality of the Church and our legitimate participation in Christ in the Church.
The whole Bible was written by the Church and acknowledge as a Canon in all its books and authors by the Church. Abraham was a member of the Church, knowing of Christ’s coming. Moses was a member of Christ and met him and wrote of him. David was a member of the Church and its earthly king and prophesied the words or Christ in the Psalms. Isaiah and all the prophets were members of the Church, telling of Jesus. Matthew, Mark, Luke, John, Paul, Peter, Jude, James, were all Catholics, and wrote of Christ to their congregations when they could not be there in person. And the Council gathered all these Scriptures together.