In his response, John Quincy Adams, at this time supposedly more orthodox than his self described "liberal unitarian Christian" father couldn't commit to belief in the infallibility of scripture or the divine inspiration of the books of Song of Solomon, Apocalypse and St. Jude.I perceive my son that you are a great Student in the Bible: I know you have been a long time; perhaps all your Life. But have you studied the Canon of Scriptures? its History? its Evidence? its Authority? In what sense do you understand the Inspiration, the Infallibility, and the Sanctity of the Books of the old and New Testament? How far do you believe them inspired? and how far not? Have you considered what is to be understood in a litteral Sense, and what in a figurative? What is History? and what is Allegory? Have you read Lardner and Jones? Have you considered the Darkness of the 3 first Centuries and the false Light of all that followed? Do you believe Solomons Song, the Apocalypse and St. Jude to be cannonical inspired and infallible.I wish you procure the Books I have mentioned for your future Use.I have a million more things to say. But Our liberal Christians and biblical Criticks are Setting up Alexander Hamilton Fisher Ames and Theophylus Parsons, as great Authorities in Support of Christianity. I dare say that not one of three knew more of the Argument than they did of Shastaism, Lamaism, or
I assume from the overall context that Adams the Sr. didn't believe those three books inspired. "[T]he Darkness of the 3 first Centuries and the false Light of all that followed ...." That's when the canon, including those three mentioned books disputed among some in the early Church and by the Christian-Deists and "liberal Christians" of John Adams' era was starting to be compiled. In fact, the canon, to the extent it was ever "settled" at all, wasn't done so until the early 4th Century and included the deuterocanonicals/apocrypha as part of sacred scripture.
Also notice how Adams trashes Alexander Hamilton's and Fisher Ames' (who were both dead by that time) understanding of the Christian faith. They were both orthodox authorities. I don't know as much about Ames' beliefs during the trajectory of his life. I know Hamilton became orthodox by the end of his life.
The overall context is Adams the elder trying to push his son's faith into a heterodox direction. And part of that heterodoxy is rejecting the orthodox -- Protestant, Catholic or whatever -- view of the biblical canon, including which books are inspired.