We should have no hesitation in reading the epistles of the New Testament and making personal application to our lives today.
The apostles intended for their letters to be shared after they were read by their initial recipients. Paul told the Colossians, "Now when this epistle is read among you, see that it is read also in the church of the Laodiceans, and that you likewise read the epistle from Laodicea" (Col. 4:16). If they were encouraged to read "other people's mail" then, we can do so with confidence today.