But Paul commended the Berians for doing just that. Testing everything with scripture. Can it be wrong? I don't think so.
scripture is not both the means and the end.
The intention is not wrong (after all, it's the intention that counts!), but we obviously do not all read the Bible the same way (yet everyone claims the same Holy Spirit as the Guide).
I think it seems plain that we neither possess the language nor mental capacity to fully understand God; nor do we have the knowledge and the feel for the history, the culture and the language of the times when different books were written.
Context: if someone comes to you telling you that something fulfills a prophecy in Scripture, one would be a fool to do anything other than search the Scriptures to see if it was so. This is what the Bereans did. In as much as the Scriptures at that time were only the Old Covenant Scriptures, if they had taken the attitude evinced by the advocates of 'sola scriptura'--that only what discursive reason could prove from Scripture was true--they would not have been commended for their action, but condemned for falling into a Judaizing heresy.
It does not follow from Paul's approval of the sensible course the Bereans took when presented with his claim that the prophecies of old had been fulfilled in Jesus Christ, that the Scriptures are a complete exposition of all that is true about God, Christ and our salvation (indeed St. John's Gospel makes a point of declaring them to be incomplete as an account of all Christ has done), still less that they give a complete account of His family's life (the original point of this thread), nor that all things salutory to salvation are recorded in them, nor does it speak against the need to interpret the Scriptures--which interpretation can only be done rightly in the context of the Church which Christ founded, and in the context of which the Christian part of the canon was written, and the canon of Scripture fixed.