noun
epistle
ih-PISS-ul/ɪˈpɪsl/
A formal or literary letter.
The unfolded epistle lies beside its opened envelope, broken wax seal, and fountain pen.

Etymology
The pieces mean 'send to,' making an epistle a message dispatched to someone. The Greek noun could also mean a command or commission, connecting the letter with its instructional use.
In context
the whole epistle of John is written to refute that heresy and passages from Paul as well
More examples
- Her epistle to the committee sets out her objections.
- The collection includes epistles exchanged by two nineteenth-century novelists.
- He opens his epistle with a formal greeting.
Forms
epistle · epistles
epistolary adjective — Written as letters or relating to letters.