Epistle scholars (which should be most all of us), please enjoy this text from Eerdmann’s.
My study of the canonization of the Pauline corpus observed that the three Pastoral Epistles were added to complete the Pauline canon within the emerging New Testament by the end of the second century. But why? It is my conclusion that these letters were included to give instructions to the custodians of Paul’s apostolic witness, now received as Scripture, and to provide both an extraordinary biography of Paul and neat theological formulae that sum up his gospel. These materials, along with the biography of a canonical Paul in Acts, provide guideposts for the church’s use of Paul’s letters in forming the wisdom necessary for salvation and the moral maturity to engage in God’s good works (cf. 2 Tim 3:15-17).[…]