Of the 27 books in the New Testament, 21 are epistles, or letters, many of which were written by Paul. But what is an epistle?

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epistle (n.)

pistle (n.)

pistol (n.)

2 Timothy 3:16-17 KJV

All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: That the man of God may be perfect, thoroughly furnished unto all good works.

https://my.bible.com/bible/1/2TI.3.16-17