Is it possible that J.McA is being brief on a topic which could easily entail twenty pages of illustration? I think so. Take just the notion of young Timothy being confronted by older, entrenched Jews who flatly opposed the Gospel of God's Grace to Gentiles. Paul assures Timothy that by adhering to the Gospel once delivered, he need not bow to the Judaisers. The letter is clear from Paul to address the issue but not spend too many words on it.
In the context of the satanic campaign of Judaising to change the simple Gospel of Grace not works to which Paul focuses Timothy's courage, the curt advice could be expanded for education, but not done in a short lesson such as these J.McA offerings.