Jude:

A surprisingly large number of the Pauline and non-Pauline Epistles confront the problem of false teachers, and almost all of them allude to it. But Jude goes beyond all other New Testament epistles in its relentless and passionate denunciation of the apostate teachers who have "crept in unnoticed" (v. 4). With the exception of its salutation (vv. 1-2) and doxology (vv.24-25), the entire epistle revolves around this alarming problem. Combining the theme of Second Peter with the…

Third John:

Third John is the shortest book in the Bible, but it is very personal and vivid. If offers a stark contrast between two men who respond in opposite ways to the itinerant teachers who have been sent out by the apostle. The faithful Gaius responds with generosity and hospitality, but the faithless Diotrephes responds with arrogance and opposition. Thus, John writes this letter to commend Gaius for walking in the truth (vv. 1-8) and to condemn Diotrephes for walking in error…