Did the Apostles Know they Were Writing Scripture?
There is no good reason to think the predication of “scripture” upon Paul’s writing is anachronistic within Paul’s lifetime.
Theology Seeking Eschatology
There is no good reason to think the predication of “scripture” upon Paul’s writing is anachronistic within Paul’s lifetime.
Paul was not a theologian, he was a pastor. Paul’s theological endeavors are secondary to his pastoral purpose; he uses theology to address and resolve pastoral problems.
The μυστήριον for Paul is less the “secret” of Christ’s Messianic identity and more like the “surprise” that the Gospel, as it is fulfilled in the resurrection and Pentecost, goes out beyond the Jews; it goes directly to the Gentiles too, and to the ends of the earth.