-From Catholic Dictionary, pg. 298
The term epistle refers to the letters written by some of the apostles, most famously St. Paul, to specific individuals or communities within the early Church. These letters, inspired by the Holy Spirit and therefore part of Sacred Scripture, were written to offer guidance and correction the Christians living in those communities. Although written almost two thousand years ago, they remain as valuable for us as they were for their original audience. For this reason, the second reading at Mass each Sunday is typically taken from one of these epistles. Because of when they were written, the epistles offer a glimpse of what the early Church looked like, the things they struggled with and the questions they had about their faith. It is remarkable how many of these things we still have trouble with today!