“How does a protty, in good faith and with the best of intentions, encourage an RC to honor his bible without ever saying anything about sola scriptura?”
First of all, you are a believer, a Christian, not a “protty”. Next, quoting scripture is not “sola scriptura”. It is the “lingua franca” of the Christians on this forum since it is the one common source that all agree on. Tradition and the Church also inform, to some with more authority than others. “But ye, brethren, be not weary in well doing” (2Th 3:13).
ena
In the end though the only source we have that judges whether Tradition, or a Church, is right is Scripture. The Church, or Tradition, don't judge whether Scripture is right.
Is. 8:20 To the law and to the testimony! If they do not speak according to this word, it is because there is no light in them.